Air conditioning unit control method and device, air conditioning unit and readable storage medium

Abstract

The application relates to an air conditioning unit control method and device, an air conditioning unit, a computer readable storage medium and a computer program product. The air conditioning unit is connected in sequence by a flash evaporator, a fin heat exchanger and a compressor, and a liquid pumping flow path is arranged between the fin heat exchanger and the flash evaporator. The suction gas superheat degree of the compressor during the operation of the air conditioning unit is continuously determined. When it is determined that there is suction liquid carrying according to the suction gas superheat degree, the liquid pumping flow path is turned on, and the liquid refrigerant in the fin heat exchanger is transported to the flash evaporator. The refrigerant state flowing through the liquid pumping flow path is determined according to the temperature before and after the liquid pumping throttling. When it is determined that there is no suction liquid carrying according to the refrigerant state flowing through the liquid pumping flow path and the suction gas superheat degree, the liquid pumping flow path is turned off. The above scheme can eliminate the suction liquid carrying phenomenon of the compressor, ensure the stable and reliable operation of the compressor, prolong the service life of the compressor, and further ensure the long-term stable operation of the air conditioning unit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioning equipment, in particular to an air conditioning unit control method and device, an air conditioning unit, a computer readable storage medium and a computer program product. BACKGROUND

[0002] With the promotion of energy saving and emission reduction plan in China, the air-cooled heat pump type air conditioning unit which can be used to replace the boiler heating is widely used, which greatly reduces environmental pollution.

[0003] In the related art, for the air-cooled heat pump type air conditioning unit, when in the low-temperature heating stage, the fin heat exchanger will have the phenomenon of suction liquid carrying due to frosting, and then the compressor is in the working state of liquid carrying compression. As known, when the compressor is in the working state of liquid carrying compression, the power consumption will be increased, and when the liquid carrying is light, a large amount of compressor oil will be taken away, which will cause the bearing of the compressor to be worn and the service life of the compressor to be reduced. When the liquid carrying is serious, the phenomenon of cylinder jamming will occur, and even the key components of the compressor will be directly damaged, which reduces the operation reliability of the compressor and is not conducive to the long-term operation. At the same time, the phenomenon of suction liquid carrying will also cause the exhaust temperature to drop and the control of the valve to be out of balance, and then the unit standby will occur frequently, which is not conducive to the stable operation of the unit. SUMMARY

[0004] Therefore, it is necessary to provide an air conditioning unit control method, device, air conditioning unit, computer readable storage medium and computer program product to solve the technical problem that the phenomenon of suction liquid carrying affects the operation reliability and stability of the air conditioning unit.

[0005] In a first aspect, the present application provides an air conditioning unit control method applied to an air conditioning unit in which a flash tank, a fin heat exchanger and a compressor are connected in sequence, a liquid suction flow path is arranged between the fin heat exchanger and the flash tank, and the method comprises:

[0006] continuously determining the suction gas superheat of the compressor in operation of the air conditioning unit;

[0007] in a case where it is determined according to the suction gas superheat of the compressor that there is suction liquid carrying, turning on the liquid suction flow path to transport the liquid refrigerant in the fin heat exchanger to the flash tank;

[0008] determining the state of the refrigerant flowing through the liquid suction flow path according to the temperature before liquid suction throttling and the temperature after liquid suction throttling, the temperature before liquid suction throttling being the temperature before a liquid suction throttle valve, the temperature after liquid suction throttling being the temperature after the liquid suction throttle valve, and the liquid suction throttle valve being arranged on the liquid suction flow path;

[0009] in a case where it is determined according to the state of the refrigerant flowing through the liquid suction flow path and the suction gas superheat that there is no suction liquid carrying, turning off the liquid suction flow path.

[0010] In one of the embodiments, a motive flow path is provided between the compressor and the flash tank, and the liquid extraction flow path merges into the flash tank through the motive flow path; the method further comprises:

[0011] In the case where it is determined that there is suction liquid carry-over according to the suction superheat of the compressor, the motive flow path is turned on to assist in transporting the liquid refrigerant in the finned heat exchanger to the flash tank;

[0012] In the case where it is determined that there is no suction liquid carry-over according to the state of the refrigerant flowing through the liquid extraction flow path and the suction superheat, the motive flow path is turned off.

[0013] In one of the embodiments, after the liquid extraction flow path and the motive flow path are turned on, the method further comprises:

[0014] In the case where the liquid extraction throttling temperature is greater than the flash tank throttling temperature, the opening of the liquid extraction throttling valve is adjusted to be smaller, the flash tank throttling temperature is the temperature after the flash tank throttling valve, and the flash tank throttling valve is located in the conventional heating flow path of the air conditioning unit;

[0015] In the case where the liquid extraction throttling temperature is equal to the flash tank throttling temperature, the current state is maintained to run;

[0016] In the case where the liquid extraction throttling temperature is less than the flash tank throttling temperature, the opening of the liquid extraction throttling valve is adjusted to be larger.

[0017] In one of the embodiments, after the opening of the liquid extraction throttling valve is adjusted, the method further comprises:

[0018] The liquid level of the flash tank is continuously detected;

[0019] In the case where the liquid level of the flash tank reaches a preset set liquid level, the openings of the flash tank throttling valve and the liquid extraction throttling valve are simultaneously adjusted to be smaller.

[0020] In one of the embodiments, the method further comprises:

[0021] In the case where it is determined that there is still suction liquid carry-over according to the suction superheat of the compressor, the openings of the flash tank throttling valve and the system throttling valve located in the conventional heating flow path are simultaneously adjusted to be smaller.

[0022] In one of the embodiments, the continuous determination of the suction superheat of the compressor in the running of the air conditioning unit comprises:

[0023] The suction end temperature and the suction end pressure of the compressor are continuously detected;

[0024] The suction end saturation temperature corresponding to the suction end pressure is determined;

[0025] determining the compressor suction superheat degree according to the suction end temperature and the suction end saturation temperature.

[0026] In one embodiment, determining the presence of suction liquid carryover according to the compressor suction superheat degree comprises: determining the presence of suction liquid carryover when the compressor suction superheat degree is negative.

[0027] In one embodiment, determining the state of the refrigerant flowing through the liquid suction flow path according to the liquid suction throttle before temperature and the liquid suction throttle after temperature comprises:

[0028] determining the liquid suction throttle before and after temperature difference according to the liquid suction throttle before temperature and the liquid suction throttle after temperature;

[0029] determining that the state of the refrigerant flowing through the liquid suction flow path is the presence of a large amount of liquid refrigerant when the liquid suction throttle before and after temperature difference is greater than or equal to a preset temperature difference threshold;

[0030] determining that the state of the refrigerant flowing through the liquid suction flow path is less liquid refrigerant when the liquid suction throttle before and after temperature difference is less than the preset temperature difference threshold.

[0031] In one embodiment, determining the absence of suction liquid carryover according to the state of the refrigerant flowing through the liquid suction flow path and the suction superheat degree comprises: determining the absence of suction liquid carryover when the state of the refrigerant flowing through the liquid suction flow path is less liquid refrigerant and the suction superheat degree is positive.

[0032] In one embodiment, when it is determined that the state of the refrigerant flowing through the liquid suction throttle valve is less liquid refrigerant, the method further comprises:

[0033] maintaining the current state of operation when the flash tank liquid level reaches a preset calibration liquid level;

[0034] increasing the opening of the liquid suction throttle valve when the flash tank liquid level does not reach the preset calibration liquid level.

[0035] In one embodiment, increasing the opening of the liquid suction throttle valve when the flash tank liquid level does not reach the preset calibration liquid level comprises:

[0036] increasing the opening of the liquid suction throttle valve by a preset multiple if the liquid suction throttle after temperature is less than the flash tank throttle after temperature.

[0037] In a second aspect, the application also provides an air conditioning unit control device, which is applied to an air conditioning unit in which a flash tank, a fin heat exchanger and a compressor are connected in sequence, a liquid suction flow path is provided between the fin heat exchanger and the flash tank, and the device comprises:

[0038] determining module, configured to continuously determine a compressor suction gas superheat degree in operation of the air conditioning unit;

[0039] conducting module, configured to, in a case where it is determined according to the compressor suction gas superheat degree that there is suction liquid entrainment, conduct the liquid extraction flow path to transport the liquid refrigerant in the fin heat exchanger to the flash tank;

[0040] judging module, configured to judge a state of the refrigerant flowing through the liquid extraction flow path according to a temperature before liquid extraction throttling and a temperature after liquid extraction throttling, the temperature before liquid extraction throttling being a temperature before a liquid extraction throttle valve, the temperature after liquid extraction throttling being a temperature after the liquid extraction throttle valve, the liquid extraction throttle valve being arranged on the liquid extraction flow path;

[0041] turning-off module, configured to, in a case where it is determined according to the state of the refrigerant flowing through the liquid extraction flow path and the suction gas superheat degree that there is no suction liquid entrainment, turn off the liquid extraction flow path.

[0042] In a third aspect, the present application further provides an air conditioning unit, comprising a flash tank, a fin heat exchanger and a compressor connected in sequence, a liquid extraction flow path being arranged between the fin heat exchanger and the flash tank, and a liquid extraction throttle valve being arranged on the liquid extraction flow path;

[0043] The air conditioning unit further comprises a controller and a temperature detection module connected with the controller, the temperature detection module being configured to detect a temperature before liquid extraction throttling and a temperature after liquid extraction throttling of the liquid extraction throttle valve, and the controller being configured to realize on-off control of the liquid extraction flow path according to the air conditioning unit control method of any one of the above to transport the liquid refrigerant in the fin heat exchanger to the flash tank.

[0044] In one of the embodiments, an ejector power flow path is arranged between the compressor and the flash tank, an ejector is arranged on the ejector power flow path, and the liquid extraction flow path merges into the flash tank through the ejector.

[0045] In one of the embodiments, a first electromagnetic valve and a one-way valve are further arranged on the liquid extraction flow path, a second electromagnetic valve is further arranged on the ejector power flow path, and the first electromagnetic valve and the second electromagnetic valve are both connected with the controller.

[0046] The first electromagnetic valve is configured to conduct or turn off the liquid extraction flow path under the control of the controller, and the second electromagnetic valve is configured to conduct or turn off the ejector power flow path under the control of the controller.

[0047] In a fourth aspect, the present application further provides a computer readable storage medium. The computer readable storage medium has a computer program stored thereon, and the computer program is executed by a processor to implement the steps of the air conditioning control method described above.

[0048] In a fifth aspect, the present application also provides a computer program product. The computer program product comprises a computer program which, when executed by a processor, implements the steps of the air conditioning unit control method described above.

[0049] The air conditioning unit control method, device, air conditioning unit, computer readable storage medium and computer program product described above are for an air conditioning unit in which a flash evaporator, a fin heat exchanger and a compressor are connected in sequence, and a liquid extraction flow path is provided between the fin heat exchanger and the flash evaporator. By continuously determining the suction gas superheat of the compressor during operation of the air conditioning unit, and in the case where it is determined that there is suction liquid carry-over according to the suction gas superheat, the liquid extraction flow path is turned on to transport the liquid refrigerant in the fin heat exchanger to the flash evaporator. Further, the temperature before and after the liquid extraction throttle valve in the liquid extraction flow path is continuously detected to determine the state of the refrigerant flowing through the liquid extraction flow path according to the temperature before and after the liquid extraction throttle, and in the case where it is determined that there is no suction liquid carry-over according to the state of the refrigerant flowing through the liquid extraction flow path and the suction gas superheat, the liquid extraction flow path is turned off. Through the above scheme, the liquid refrigerant in the fin heat exchanger can be transported to the flash evaporator to eliminate the suction liquid carry-over phenomenon of the compressor, ensure stable and reliable operation of the compressor, improve the service life of the compressor, and further ensure long-term stable operation of the air conditioning unit. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the description of the embodiments of the present application or the related art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other related drawings can be obtained by those skilled in the art without creative labor.

[0051] Figure 1 A system block diagram of an air conditioning unit in an embodiment;

[0052] Figure 2 A flowchart of an air conditioning unit control method in an embodiment;

[0053] Figure 3 A system block diagram of an air conditioning unit in another embodiment;

[0054] Figure 4 A flowchart of an air conditioning unit control method in another embodiment;

[0055] Figure 5 A flowchart of an air conditioning unit control method in another embodiment;

[0056] Figure 6 A flowchart of an air conditioning unit control method in another embodiment;

[0057] Figure 7 Flowchart of the air conditioning unit control method of another embodiment;

[0058] Figure 8 Flowchart of the air conditioning unit control method of another embodiment;

[0059] Figure 9 Flowchart of the air conditioning unit control method of another embodiment;

[0060] Figure 10 Flowchart of the air conditioning unit control method of another embodiment;

[0061] Figure 11 Flowchart of the air conditioning unit control method of another embodiment;

[0062] Figure 12 Structural block diagram of the air conditioning unit control device of an embodiment;

[0063] Figure 13 Internal structural diagram of the computer device of an embodiment. DETAILED DESCRIPTION

[0064] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0065] In the related art, for the air-cooled heat pump type air conditioning unit, when in the low-temperature heating stage, the fin heat exchanger will have the phenomenon of suction liquid carrying due to frosting, and then the compressor will be in the working state of liquid carrying compression. As known, the compressor will increase power consumption when in the working state of liquid carrying compression, and a large amount of compressor oil will be carried away when the liquid carrying is light, which will cause the bearing of the compressor to wear and reduce the service life of the compressor. When the liquid carrying is serious, the phenomenon of cylinder jamming will occur, and even the key components of the compressor will be directly damaged, which reduces the operation reliability of the compressor and is not conducive to long-term operation. At the same time, the phenomenon of suction liquid carrying will also cause the exhaust temperature to drop, the control of the valve to be out of balance, and then the standby of the unit to occur frequently, which is not conducive to the stable operation of the unit.

[0066] During the heating operation, due to the influence of environmental humidity, the fin heat exchanger will inevitably frost, and in order to improve the condition of compressor suction liquid carrying, the whereabouts of the liquid refrigerant in the fin heat exchanger need to be solved. In the conventional air conditioning unit, a vapor-liquid separator will be added at the suction port of the compressor to separate the liquid refrigerant. However, the addition of the vapor-liquid separator will not only increase the cost of the unit, but also cause a part of the refrigerant not to participate in the circulation. In addition, the vapor-liquid separator itself will also cause a large pressure drop, which also reduces the energy efficiency of the unit.

[0067] The air conditioning unit control method provided by the embodiments of the present application can be applied to the application environment as shown in Figure 1 The air conditioning unit includes a flasher 4, a fin heat exchanger 6 and a compressor 1 connected in sequence, a liquid extraction flow path a is arranged between the fin heat exchanger 6 and the flasher 4, and a liquid extraction throttle valve 9 is arranged on the liquid extraction flow path a. The air conditioning unit further includes a controller and a temperature detection module (not shown in the figure) connected to the controller, the temperature detection module is used to detect the liquid extraction pre-throttling temperature and the liquid extraction post-throttling temperature of the liquid extraction throttle valve 9, and the controller is used to realize on-off control of the liquid extraction flow path a according to the air conditioning control method provided by the embodiments of the present application, so as to transport the liquid refrigerant in the fin heat exchanger 6 to the flasher 4. It can be understood that the controller used to control the air conditioning unit can be a controller arranged directly in the air conditioning unit, or an external control system realized based on wireless communication.

[0068] In an exemplary embodiment, as shown in Figure 2 An air conditioning unit control method is provided, and the method is applied to the controller in Figure 1 for example, and includes the following steps 202 to 208. Wherein:

[0069] Step 202, continuously determine the compressor suction superheat degree in the operation of the air conditioning unit;

[0070] It can be understood with reference to Figure 1 For the conventional heating mode, under the control of the four-way valve, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 enters the hot water heat exchanger 2 to exchange heat with water to obtain hot water, and the high-temperature and high-pressure refrigerant gas is condensed into high-pressure and medium-temperature liquid refrigerant at this position. Then, after throttling through the flasher throttle valve 3, the liquid refrigerant enters the flasher 4, evaporates by reducing pressure with condensate water, reduces the temperature of the liquid refrigerant, and recovers part of the gas refrigerant to the compressor 1 to realize air supplementing, so as to improve the heating performance. The low-temperature and low-pressure liquid refrigerant from the liquid outlet of the flasher 4 is subjected to secondary throttling through the system throttle valve 5, enters the fin heat exchanger 6, and exchanges heat with air under the action of the fan in the fin heat exchanger 6, and is evaporated into low-temperature and low-pressure gas refrigerant and returns to the compressor 1 to complete the heating refrigerant cycle. Correspondingly, the suction liquid carrying phenomenon refers to that in the heating refrigerant cycle process, the heat exchange may not be sufficient due to frosting of the fin heat exchanger 6, and the refrigerant returning to the compressor 1 is gas-liquid mixed refrigerant carrying liquid.

[0071] Further, in the operation process of the air conditioning unit, whether the compressor suction liquid carrying exists can be determined by determining the compressor suction superheat degree. The compressor suction superheat degree represents the suction superheat degree of the suction port of the compressor, and the suction superheat degree represents the temperature value of the refrigerant from the fin heat exchanger, which is increased due to heat absorption before entering the compressor through the return pipe.

[0072] Exemplarily, the suction superheat of the compressor can be determined by the suction port temperature of the compressor and the outlet temperature of the finned heat exchanger, or by the suction port temperature of the compressor and the suction port pressure and the like.

[0073] It can be understood that, in the case that the suction superheat indicates that the gaseous refrigerant has not increased in temperature, or even has decreased in temperature, it can be determined that the refrigerant entering the compressor has a liquid form, and the suction liquid phenomenon occurs. Conversely, in the case that the suction superheat indicates that the gaseous refrigerant has increased in temperature, it can be determined that the suction liquid phenomenon does not occur.

[0074] In an exemplary embodiment, determining that the suction liquid phenomenon exists according to the suction superheat of the compressor includes: determining that the suction liquid phenomenon exists when the suction superheat of the compressor is negative.

[0075] It can be understood that, when the suction superheat of the compressor is negative, that is, the temperature value of the refrigerant decreases before the refrigerant from the finned heat exchanger enters the compressor through the return pipe, it can be determined that the refrigerant entering the compressor has a liquid form, and the suction liquid phenomenon occurs.

[0076] Specifically, whether the suction superheat of the compressor is negative can be determined by comparing the suction superheat with a preset temperature threshold. The preset temperature threshold can be set to 0℃, or can be set to a temperature value slightly lower than 0℃ (0~-1℃). Further, in the case that the suction superheat is less than the preset temperature threshold, it indicates that the suction superheat is negative, and it is determined that the suction liquid phenomenon exists. In the case that the suction superheat is greater than or equal to the preset temperature threshold, it indicates that the suction superheat is positive, and it is determined that the suction liquid phenomenon does not exist.

[0077] Step 204, in the case that it is determined that the suction liquid phenomenon exists according to the suction superheat of the compressor, the liquid pumping flow path is turned on, and the liquid refrigerant in the finned heat exchanger is transported to the flash evaporator.

[0078] Specifically, in the case that it is determined that the suction liquid phenomenon exists according to the suction superheat of the compressor, the liquid pumping flow path needs to be turned on, and the liquid pumping state is entered, so as to pump away the liquid refrigerant on the flow path from the finned heat exchanger to the compressor, to ensure that the suction port of the compressor does not suck in the liquid refrigerant, and to ensure the stable and safe operation of the compressor and the air conditioning unit.

[0079] The liquid pumping flow path is used to pump liquid at the outlet pipe position of the finned heat exchanger, and to supplement liquid to the flash evaporator, so as to transport the liquid refrigerant in the finned heat exchanger to the flash evaporator, and to solve the suction liquid problem.

[0080] It can be understood that, since the side of the flash evaporator belongs to the medium pressure end, and the side of the finned heat exchanger belongs to the low pressure end. According to the conventional principle, the low pressure end cannot flow into the medium pressure end by itself, and auxiliary power needs to be added. Exemplarily, refer to Figure 1A booster 8 can be arranged on the liquid extraction flow path to provide power for the fin heat exchanger side, so that the low-pressure end refrigerant effectively enters the medium-pressure end.

[0081] Further, a switching device, such as an electromagnetic valve, can also be arranged on the liquid extraction flow path to, under the control of the controller, determine that there is liquid entrainment after suction, and then turn on the liquid extraction flow path to transport the liquid refrigerant in the fin heat exchanger to the flash evaporator.

[0082] In step 206, the state of the refrigerant flowing through the liquid extraction flow path is determined according to the temperature before and after the liquid extraction throttling. The temperature before the liquid extraction throttling is the temperature before the liquid extraction throttle valve, and the temperature after the liquid extraction throttling is the temperature after the liquid extraction throttle valve.

[0083] The liquid extraction throttle valve is arranged on the liquid extraction flow path to control the flow of the refrigerant on the liquid extraction flow path. It can be understood that the temperature difference of the normal liquid refrigerant passing through the throttle is very obvious, while the temperature difference of the gaseous refrigerant passing through the throttle is not obvious. Further, the temperature difference of the refrigerant flowing before and after the liquid extraction throttle valve can be used to determine the state of the refrigerant flowing through the liquid extraction flow path.

[0084] Specifically, when in the liquid extraction state, the temperature detection module is connected to the front and back sides of the liquid extraction throttle valve to detect the liquid extraction pre-throttling temperature before the liquid extraction throttle valve and the liquid extraction post-throttling temperature after the liquid extraction throttle valve. Then, the liquid extraction pre-throttling temperature and the liquid extraction post-throttling temperature are compared to obtain the temperature difference to determine whether there is still liquid refrigerant flowing through the liquid extraction flow path, and further determine when to exit the liquid extraction state and restore the normal operation of each component of the air conditioning unit to avoid affecting the heating efficiency of the air conditioning unit for a long time.

[0085] It can be understood that when the temperature difference between the liquid extraction pre-throttling temperature and the liquid extraction post-throttling temperature is greater than or equal to a preset temperature difference threshold, it is determined that the state of the refrigerant flowing through the liquid extraction flow path is that there is still a large amount of liquid refrigerant; and when the temperature difference between the liquid extraction pre-throttling temperature and the liquid extraction post-throttling temperature is less than the preset temperature difference threshold, it is determined that the state of the refrigerant flowing through the liquid extraction flow path is that there is less liquid refrigerant. The value of the preset temperature difference threshold can be obtained by pre-test according to the technical specifications and technical needs of the liquid extraction throttle valve, as long as it can determine the state of the refrigerant flowing through the liquid extraction flow path. In the embodiment of the present application, the preset temperature difference threshold is usually valued between 3-8℃.

[0086] In addition, when the liquid extraction flow path is turned on, the opening of the liquid extraction throttle valve can be adjusted to an initial opening value. The initial opening value can be set according to actual needs. In order to avoid too large causing system shock and too small leading to obvious liquid extraction effect, the initial opening value corresponding to the liquid extraction throttle valve is valued at 30%-50% in this embodiment.

[0087] Step 208, in the case of determining no suction liquid carrying according to the state of the refrigerant flowing through the liquid extraction flow path and the suction superheat, the liquid extraction flow path is shut off.

[0088] It can be understood that in the case of the state of the refrigerant flowing through the liquid extraction flow path being less liquid refrigerant, and the suction superheat also indicating the temperature of the gaseous refrigerant increasing, it can be determined that there is no suction liquid carrying phenomenon, and the liquid extraction control can be exited to restore the normal operation of the air conditioning unit.

[0089] Specifically, when it is determined that there is no suction liquid carrying phenomenon, the liquid extraction flow path can be shut off, the liquid extraction state is exited, and the refrigerant extraction of the air outlet pipe position of the fin heat exchanger is stopped to avoid the long-time refrigerant extraction affecting the heating efficiency of the air conditioning unit.

[0090] Further, shutting off the liquid extraction flow path can be controlling the on-off device provided on the liquid extraction flow path to stop running, and stopping the refrigerant of the air outlet pipe position of the fin heat exchanger from being delivered to the flash evaporator.

[0091] The above air conditioning unit control method realizes the delivery of the liquid refrigerant of the air outlet pipe position of the fin heat exchanger to the flash evaporator by adding the liquid extraction flow path to the flash evaporator at the air outlet pipe position of the fin heat exchanger, and combines the suction superheat detection to solve the suction liquid carrying problem, ensure the stable and reliable operation of the compressor, and improve the service life of the compressor. At the same time, by judging the state of the refrigerant flowing through the liquid extraction flow path through the temperature difference before and after the liquid extraction throttle valve on the liquid extraction flow path, the liquid extraction is stopped in time in the case of no suction liquid carrying to avoid the long-time refrigerant extraction affecting the heating efficiency of the air conditioning unit, and further ensure the long-term stable operation of the air conditioning unit.

[0092] In an exemplary embodiment, referring to Figure 3 , a suction power flow path b is provided between the compressor 1 and the flash evaporator 4, and the liquid extraction flow path a flows into the flash evaporator 4 through the suction power flow path b.

[0093] It can be understood that since the flash evaporator 4 belongs to the medium pressure end, and the fin heat exchanger 6 belongs to the low pressure end, the refrigerant on the fin heat exchanger side cannot flow into the flash evaporator side by itself, and needs to increase auxiliary power. In this embodiment, based on the fact that the exhaust port of the compressor 1 is the high pressure end, and further considering that the flow can be introduced to the flash evaporator 4 by increasing the suction power flow path b from the exhaust end of the compressor 1, and the liquid extraction flow path a flows into the suction power flow path b, so as to provide the liquid extraction flow path a with the power to flow into the flash evaporator 4 through the suction power flow path b.

[0094] Exemplarily, the suction power flow path b can be realized by an ejector 8.

[0095] It can be understood that the ejector 8 can use a high-speed high-energy flow (liquid flow, gas flow or other material flow) to eject another low-speed low-energy flow. Specifically, the primary fluid is ejected into the mixing chamber through the converging nozzle at a high speed to form a jet flow to generate a suction flow to form a negative pressure area in the mixing chamber, and the suction fluid is mixed into the mixing chamber for mixing, and then the mixed fluid enters the diffuser chamber, and the pressure increases due to the decrease of the flow rate. At the outlet of the diffuser chamber, the pressure of the mixed fluid is higher than that of the ejecting fluid entering the mixing chamber, and the mixed fluid is finally emitted after being damped and purified in the muffler.

[0096] In this embodiment, since the ejector 8 has no mechanical moving parts, it is not limited by conditions such as friction, lubrication and vibration, and compared with providing power through a booster pump, it can avoid additional energy consumption of the air conditioning unit on the basis of realizing the flow. At the same time, the gas refrigerant of the compressor 1 is introduced into the flash evaporator 4, which can also enhance the gas supply effect of the flash evaporator 4, so that the operating state of the air conditioning unit is more optimal.

[0097] Correspondingly, as shown in Figure 4 , the air conditioning unit control method further includes steps 302 to 304. Among them:

[0098] Step 302: When it is determined that there is suction liquid carrying according to the suction gas superheat degree, the ejector power flow path is turned on to assist the delivery of the liquid refrigerant in the fin heat exchanger to the flash evaporator.

[0099] Specifically, when it is determined that there is suction liquid carrying according to the suction gas superheat degree, the ejector power flow path b is turned on at the same time as the liquid suction flow path a is turned on. The refrigerant on the ejector power flow path b is realized by the ejector to flow from the compressor to the flash evaporator, to provide power for the liquid suction flow path a to flow into the flash evaporator, to assist the delivery of the liquid refrigerant in the fin heat exchanger to the flash evaporator, to ensure that the suction port of the compressor does not suck in liquid carrying refrigerant, and to ensure the stable and safe operation of the compressor and the air conditioning unit.

[0100] It can be understood that a switching device such as a solenoid valve can be provided on the ejector power flow path b, so as to be controlled by the controller to determine that there is suction liquid carrying, and to turn on the ejector power flow path b to provide power for the liquid suction flow path a to flow into the flash evaporator, to assist the delivery of the liquid refrigerant in the fin heat exchanger to the flash evaporator.

[0101] Step 304: When it is determined that there is no suction liquid carrying according to the state of the refrigerant flowing through the liquid suction flow path and the suction gas superheat degree, the ejector power flow path is turned off.

[0102] Specifically, when the state of the refrigerant flowing through the liquid suction flow path is that there is less liquid refrigerant, and the suction gas superheat degree also indicates that the temperature of the gas refrigerant is increased, it can be determined that there is no suction liquid carrying phenomenon, and the liquid suction control can be exited to restore the normal operation of the air conditioning unit.

[0103] Further, when the suction flow path a is turned off, the ejector power flow path b is also turned off, the suction control is exited, and the normal operation of the air conditioning unit is restored to avoid affecting the heating efficiency of the air conditioning unit for a long time.

[0104] The turning off of the ejector power flow path b can be controlling a switching device arranged on the ejector power flow path b to stop running and stop transporting the refrigerant at the compressor exhaust port position to the flash evaporator.

[0105] It can be understood that during the process of extracting the refrigerant from the compressor to the finned heat exchanger to the flash evaporator, it is necessary to pay attention to whether the refrigerant supplemented into the flash evaporator will affect the flashing effect of the flash evaporator, thereby affecting the normal heating of the air conditioning unit.

[0106] Specifically, referring to Figure 3 , the refrigerant temperature T9 flowing into the flash evaporator 4 from the suction throttle valve 9 and the refrigerant temperature T3 flowing into the flash evaporator 4 from the flash evaporator throttle valve 3 are compared. 9后 If the refrigerant temperature T9 is greater than the refrigerant temperature T3, it indicates that the refrigerant supplemented into the flash evaporator will affect the flashing effect of the flash evaporator, and the refrigerant temperature supplemented into the flash evaporator needs to be appropriately reduced. 9后 If the refrigerant temperature T9 is less than the refrigerant temperature T3, it indicates that the amount of refrigerant supplemented into the flash evaporator is too large, and the amount of air supplement is too much, which will increase the load of the compressor and easily trigger the overload protection, so the refrigerant temperature supplemented into the flash evaporator needs to be increased to reduce the evaporation amount of the flash evaporator. 9后

[0107] Correspondingly, in an exemplary embodiment, as shown in Figure 5 , after the turning on of the suction flow path in step 204 and the turning on of the ejector power flow path in step 302, the air conditioning unit control method further includes steps 402 to 406. Among them:

[0108] Step 402, in the case that the suction throttle temperature is greater than the flash evaporator throttle temperature, the opening of the suction throttle valve is adjusted to be smaller, and the flash evaporator throttle temperature is the temperature after the flash evaporator throttle valve.

[0109] Among them, the suction throttle temperature, i.e. the refrigerant temperature T9 flowing into the flash evaporator 4 from the suction throttle valve 9. 9后 The flash evaporator throttle temperature, i.e. the refrigerant temperature T3 flowing into the flash evaporator 4 from the flash evaporator throttle valve 3.

[0110] Specifically, in the case that the suction throttle temperature is greater than the flash evaporator throttle temperature, i.e. the refrigerant temperature T9 is greater than the refrigerant temperature T3, it indicates that the refrigerant supplemented into the flash evaporator will affect the flashing effect of the flash evaporator, and the refrigerant temperature supplemented into the flash evaporator needs to be appropriately reduced.​9后 When the refrigerant temperature T3 is greater than the refrigerant temperature T2, the opening of the liquid pumping throttle valve 9 needs to be adjusted to reduce the throttling effect to avoid the influence of the refrigerant temperature supplied to the flash evaporator on the flash evaporation effect of the flash evaporator.

[0111] Step 404, in the case where the temperature after liquid pumping throttling is equal to the temperature after flash evaporator throttling, the current state is maintained to run.

[0112] It can be understood that, in the case where the temperature after liquid pumping throttling is equal to the temperature after flash evaporator throttling, that is, the refrigerant temperature T2 is equal to the refrigerant temperature T3, the refrigerant temperature supplied to the flash evaporator has no influence on the flash evaporation effect of the flash evaporator, and no adjustment is needed. 9后 When the refrigerant temperature T3 is equal to the refrigerant temperature T2, the refrigerant temperature supplied to the flash evaporator has no influence on the flash evaporation effect of the flash evaporator, and no adjustment is needed.

[0113] Step 406, in the case where the temperature after liquid pumping throttling is less than the temperature after flash evaporator throttling, the opening of the liquid pumping throttle valve is adjusted to be increased.

[0114] Specifically, in the case where the temperature after liquid pumping throttling is less than the temperature after flash evaporator throttling, that is, the refrigerant temperature T2 is less than the refrigerant temperature T3, the opening of the liquid pumping throttle valve 9 needs to be adjusted to be increased to increase the refrigerant temperature after throttling of the liquid pumping throttle valve 9 and reduce the evaporation amount of the flash evaporator. 9后 When the refrigerant temperature T3 is less than the refrigerant temperature T2, the opening of the liquid pumping throttle valve 9 needs to be adjusted to be increased to increase the refrigerant temperature after throttling of the liquid pumping throttle valve 9 and reduce the evaporation amount of the flash evaporator.

[0115] It can be understood that, in the adjustment process of the liquid pumping throttle valve, the liquid level of the refrigerant in the flash evaporator also needs to be continuously monitored to avoid that the liquid level of the flash evaporator is too high to seriously affect the flash evaporation effect and to avoid that the liquid level of the flash evaporator is too low to cause the gaseous refrigerant to directly rush to the system throttle valve, resulting in poor throttling of the main circuit.

[0116] In an exemplary embodiment, as shown in FIG. 5, the air conditioning unit control method further includes steps 502 to 504. Among them: Figure 6 Step 502, continuously detecting the liquid level of the flash evaporator.

[0117] Specifically, the liquid level of the flash evaporator can be obtained by a liquid level detection device connected to the inside of the flash evaporator. In the embodiments of the present application, the liquid level of the flash evaporator can be continuously detected after the adjustment of the liquid pumping throttle valve or in the process of liquid pumping to monitor whether the liquid level of the flash evaporator is out of limit.

[0118] Step 504, in the case where the liquid level of the flash evaporator reaches a preset calibration liquid level, the openings of the flash evaporator throttle valve and the liquid pumping throttle valve are simultaneously adjusted to be reduced.

[0119]

[0120] ​Specifically, in the case that the flash tank liquid level reaches the preset calibration liquid level, it is characterized that there is a risk of affecting the flash effect, and the amount of refrigerant flowing into the flash tank needs to be reduced to prevent the liquid level in the flash tank from being too high. Correspondingly, the method of reducing the amount of refrigerant flowing into the flash tank can be achieved by adjusting the opening of the flash tank throttle valve on the conventional heating flow path, or by adjusting the opening of the liquid pumping throttle valve on the liquid pumping flow path, or by adjusting the opening of the above two throttle valves. In this application, in the case that the flash tank liquid level reaches the preset calibration liquid level, the opening of the flash tank throttle valve and the liquid pumping throttle valve is simultaneously reduced to reduce the amount of refrigerant flowing into the flash tank.

[0121] The value of the preset calibration liquid level is not fixed and can be determined after preliminary testing according to the specifications of the flash tank actually used in the air conditioning unit. As long as the purpose of judging that the flash tank liquid level exceeds the preset calibration liquid level will affect the flash effect can be met. In this embodiment, the preset calibration liquid level is usually set to between 1 / 3 and 2 / 3 of the overall capacity of the flash tank.

[0122] It can be understood that after being in the liquid pumping state and adjusting the flash tank throttle valve and the liquid pumping throttle valve through step 504, the compressor suction superheat degree needs to be continuously monitored to ensure that the liquid pumping process improves the situation of liquid entrainment in the compressor suction.

[0123] In an exemplary embodiment, the air conditioning unit control method further comprises: simultaneously reducing the opening of the flash tank throttle valve and the system throttle valve located on the conventional heating flow path when it is determined that there is still liquid entrainment in the compressor suction according to the compressor suction superheat degree.

[0124] It can be understood that after adjusting the flash tank throttle valve and the liquid pumping throttle valve in step 504, the compressor suction superheat degree needs to be determined again, and the liquid entrainment condition is judged according to the compressor suction superheat degree. If the compressor suction superheat degree determined again indicates that the temperature of the gas refrigerant has not been raised or is still in a state of temperature reduction, it indicates that the refrigerant coming out of the finned heat exchanger still has a lot of liquid, and further measures need to be taken to reduce the refrigerant flow to quickly solve the liquid entrainment phenomenon.

[0125] Specifically, in the case that it is determined that there is still liquid entrainment in the compressor suction according to the compressor suction superheat degree, i.e. the compressor suction superheat degree determined again is still negative, the opening of the flash tank throttle valve and the system throttle valve is simultaneously reduced to reduce the amount of refrigerant on the conventional heating flow path, so as to reduce the amount of refrigerant flowing into the finned heat exchanger and speed up the rate of solving the liquid entrainment phenomenon. At the same time, the amount of refrigerant on the liquid pumping flow path and the injection power flow path does not need to be adjusted and can remain in the current state.

[0126] In addition, in the case that the compressor suction superheat degree is determined to be positive again, the effect of liquid extraction is represented, and the liquid-carrying condition of the compressor suction is improved, then no adjustment is needed, and the current operation state can be maintained.

[0127] Exemplarily, the opening of the flash tank throttle valve and the system throttle valve in this step can be directly adjusted to the minimum opening value. The minimum opening value can be an opening value set to 10% to 20%.

[0128] In an exemplary embodiment, as shown in FIG. 6, step 202 includes steps 602 to 606. Among them: Figure 7

[0129] Step 602: Continuously detect the suction end temperature T L and the suction end pressure P L of the compressor.

[0130] Specifically, the suction end temperature T L and the suction end pressure P L of the compressor are the temperature and pressure corresponding to the suction port of the compressor. Among them, the suction end temperature T L can be detected by a temperature detection module, and the suction end pressure P L can be detected by a pressure detection module.

[0131] Step 604: Determine the corresponding suction end saturation temperature according to the suction end pressure.

[0132] It can be understood that for the refrigerant, the pressure value and the saturation temperature are one-to-one corresponding, for example, the refrigerant with a pressure of 0.49 MPa has a saturation temperature of 5°C. Further, based on the one-to-one correspondence between the pressure and the saturation temperature, the corresponding suction end saturation temperature can be determined according to the detected suction end pressure P L .

[0133] Step 606: Determine the compressor suction superheat degree according to the suction end temperature T L and the suction end saturation temperature.

[0134] Specifically, the compressor suction superheat degree can be determined based on the difference or ratio of the suction end temperature T L and the suction end saturation temperature. In this embodiment, the difference between the suction end temperature T L and the suction end saturation temperature is taken as the compressor suction superheat degree.

[0135] In an exemplary embodiment, as shown in FIG. 7, step 206 includes steps 702 to 706. Among them: Figure 8

[0136] ​​Step 702, determining the temperature difference before and after the liquid throttling according to the temperature before the liquid throttling and the temperature after the liquid throttling.

[0137] Specifically, the temperature difference before and after the liquid throttling, i.e. the temperature difference between the temperature before the liquid throttling and the temperature after the liquid throttling, can be compared with the preset temperature difference threshold to determine the state of the refrigerant flowing through the liquid flow path.

[0138] Step 704, in the case that the temperature difference before and after the liquid throttling is greater than or equal to the preset temperature difference threshold, determining that the state of the refrigerant flowing through the liquid flow path is that there is a large amount of liquid refrigerant.

[0139] Specifically, in the case that the temperature difference before and after the liquid throttling is greater than or equal to the preset temperature difference threshold, it indicates that the throttling effect is strong at this time, and there is still a large amount of liquid refrigerant passing through, i.e. it can be determined that the state of the refrigerant flowing through the liquid flow path is that there is a large amount of liquid refrigerant.

[0140] Step 706, in the case that the temperature difference before and after the liquid throttling is less than the preset temperature difference threshold, determining that the state of the refrigerant flowing through the liquid flow path is that there is less liquid refrigerant.

[0141] Specifically, in the case that the temperature difference before and after the liquid throttling is less than the preset temperature difference threshold, it indicates that the liquid refrigerant flowing through the liquid throttling valve is already relatively small at this time, i.e. it can be determined that the state of the refrigerant flowing through the liquid flow path is that there is less liquid refrigerant.

[0142] Correspondingly, in an exemplary embodiment, the determining no suction liquid carrying according to the state of the refrigerant flowing through the liquid flow path and the suction superheat in step 208 comprises: the state of the refrigerant flowing through the liquid flow path is less liquid refrigerant, and the suction superheat is positive, then determining no suction liquid carrying.

[0143] In an exemplary embodiment, in the case that the state of the refrigerant flowing through the liquid throttling valve is less liquid refrigerant, the next step control can be performed to quickly end the liquid pumping state. Correspondingly, as shown in Figure 9 The above air conditioning unit control method further comprises steps 802 to 804. Among them:

[0144] Step 802, in the case that the flash tank liquid level reaches the preset calibration liquid level, maintaining the current state running.

[0145] Step 804, in the case that the flash tank liquid level does not reach the preset calibration liquid level, increasing the opening of the liquid throttling valve.

[0146] It can be understood that, on the basis of solving the problem of suction liquid carrying through the liquid flow path and the motive flow path, the flash tank liquid level can also be controlled to be close to the preset calibration liquid level to ensure the optimal flashing effect of the flash tank, and further ensure the heating efficiency of the air conditioning unit.

[0147] Specifically, if the flash evaporator level reaches the preset calibration level, simply maintain the current operation. If the flash evaporator level does not reach the preset calibration level, the opening of the liquid extraction throttle valve can be increased to increase the amount of refrigerant supplied to the flash evaporator and raise the flash evaporator level.

[0148] Furthermore, in an exemplary embodiment, step 704 includes: if the temperature after throttling is lower than the temperature after throttling of the flash evaporator, increasing the opening of the throttling valve by a preset multiple.

[0149] As described above, the temperature after liquid extraction and throttling (the temperature T of the refrigerant flowing from the liquid extraction and throttling valve 9 into the flash evaporator 4) is... 9后 If the temperature is less than the temperature after throttling in the flash evaporator (T3, the temperature of the refrigerant flowing from the flash evaporator throttling valve 3 into the flash evaporator 4), it indicates that the amount of refrigerant added to the flash evaporator is too large, and the amount of gas added is too much. This will increase the compressor load and easily trigger overload protection. It is necessary to increase the opening of the liquid extraction throttling valve, increase the temperature of the refrigerant added to the flash evaporator, and reduce the evaporation rate of the flash evaporator.

[0150] Therefore, when the liquid level in the flash evaporator reaches the preset calibration level, and the temperature after throttling is lower than the temperature after throttling in the flash evaporator, the opening of the throttling valve needs to be increased in both cases. This can be achieved by increasing the opening of the throttling valve by a preset multiple to meet the refrigerant supply requirements to the flash evaporator. The preset multiple can be determined based on the actual refrigerant demand. In this embodiment, to avoid excessive adjustment steps that could cause system oscillation, a preset multiple of 2 is used as an example. That is, under the above conditions, the opening of the throttling valve can be increased by 2 times.

[0151] For example, in any of the above embodiments, the adjustment of throttle valves such as the flash generator throttle valve, the liquid extraction throttle valve, and the system throttle valve can be performed by increasing or decreasing the adjustment step by step. The value of the fixed step is not limited; however, to avoid ineffective adjustment due to excessively small adjustments or ineffective liquid extraction due to excessively large adjustments, the fixed step in this embodiment can be between 1% and 5%.

[0152] It should be understood that, although the steps in the flowcharts involved in the embodiments described above are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other sequences. Moreover, at least some of the steps in the flowcharts involved in the embodiments described above can include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of these steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least part of other steps or steps or stages in other steps.

[0153] In an exemplary embodiment, as shown in Figure 1 An air conditioning unit is provided, which includes a flasher 4, a fin heat exchanger 6 and a compressor 1 connected in sequence, a liquid extraction flow path a is provided between the fin heat exchanger 6 and the flasher 4, and a liquid extraction throttle valve 9 is provided on the liquid extraction flow path a. The air conditioning unit further comprises a controller and a temperature detection module (not shown in the figure) connected to the controller, the temperature detection module is used to detect the liquid extraction throttle before and after the liquid extraction throttle of the liquid extraction throttle valve 9, and the controller is used to realize the on-off control of the liquid extraction flow path a according to the air conditioning control method provided by the embodiments of the present application, so as to transport the liquid refrigerant in the fin heat exchanger 6 to the flasher 4.

[0154] It can be understood that, with reference to Figure 1 For the conventional heating mode, under the control of the four-way valve, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 enters the hot water heat exchanger 2 to exchange heat with water to produce hot water, and the high-temperature and high-pressure refrigerant gas is condensed into high-pressure medium-temperature liquid refrigerant at this point. Then, after throttling through the flasher throttle valve 3, it enters the flasher 4, evaporates by reducing pressure using condensate water, reduces the temperature of the liquid refrigerant, and recovers part of the gas refrigerant to the compressor 1 to realize air charging and improve the heating performance. The low-temperature and low-pressure liquid refrigerant from the liquid outlet of the flasher 4 is subjected to secondary throttling through the system throttle valve 5, enters the fin heat exchanger 6, and is subjected to heat exchange with air under the action of the internal fan of the fin heat exchanger 6, evaporates into low-temperature and low-pressure gas refrigerant, and returns to the compressor 1 to complete the heating refrigerant cycle. Correspondingly, the suction liquid phenomenon refers to that, in the heating refrigerant cycle process, the heat exchange may not be sufficient due to frosting of the fin heat exchanger 6, and the refrigerant returning to the compressor 1 is gas-liquid mixed refrigerant with liquid.

[0155] Further, in the operation process of the air conditioning unit, whether the compressor suction liquid entrainment exists can be determined by determining the compressor suction superheat. The compressor suction superheat represents the suction superheat of the suction port of the compressor, and the suction superheat represents the temperature value of the refrigerant from the fin heat exchanger that is increased due to heat absorption before entering the compressor through the gas return pipe.

[0156] For example, the compressor suction superheat can be determined by the suction port temperature of the compressor and the outlet temperature of the fin heat exchanger, or can be determined by the suction port temperature of the compressor and the suction port pressure and the like.

[0157] It can be understood that in the case that the suction superheat represents that the gaseous refrigerant has not increased the temperature, or even has decreased the temperature, it can be determined that the refrigerant entering the compressor has liquid form, and the suction liquid entrainment phenomenon occurs. Conversely, in the case that the suction superheat represents that the gaseous refrigerant has increased the temperature, it can be determined that the suction liquid entrainment phenomenon does not occur.

[0158] Specifically, in the case that the suction liquid entrainment is determined to exist according to the compressor suction superheat, the liquid extraction flow path needs to be turned on to enter the liquid extraction state, and the liquid refrigerant in the flow path from the fin heat exchanger to the compressor is extracted to ensure that the suction port of the compressor does not suck the liquid refrigerant, and to ensure the stable and safe operation of the compressor and the air conditioning unit.

[0159] The liquid extraction flow path is used to extract liquid at the gas outlet pipe position of the fin heat exchanger, and to supplement liquid to the flash evaporator, so as to transport the liquid refrigerant in the fin heat exchanger to the flash evaporator, and solve the problem of suction liquid entrainment.

[0160] It can be understood that the flash evaporator side belongs to the medium pressure end, and the fin heat exchanger side belongs to the low pressure end. According to the conventional principle, the low pressure end cannot flow into the medium pressure end by itself, and needs to increase auxiliary power. For example, referring to Figure 1 A pressure increasing device 8 can be provided on the liquid extraction flow path to provide power for the fin heat exchanger side, so that the low pressure end refrigerant can effectively enter the medium pressure end.

[0161] Further, a switching device such as an electromagnetic valve can also be provided on the liquid extraction flow path, so as to be controlled by the controller to determine that the suction liquid entrainment exists, and then turn on the liquid extraction flow path to transport the liquid refrigerant in the fin heat exchanger to the flash evaporator.

[0162] The liquid extraction throttle valve is provided on the liquid extraction flow path to control the flow of the refrigerant on the liquid extraction flow path. It can be understood that the normal liquid refrigerant will produce a very obvious temperature difference after throttling, while the gaseous refrigerant will not produce a very obvious temperature difference after throttling. Further, the temperature difference of the refrigerant before and after flowing through the liquid extraction throttle valve can be used to determine the state of the refrigerant flowing through the liquid extraction flow path.

[0163] Specifically, when in the liquid pumping state, the temperature detection module can be connected to the front and rear sides of the liquid pumping throttle valve to detect the liquid pumping pre-throttle temperature and the liquid pumping post-throttle temperature. Then, the liquid pumping pre-throttle temperature and the liquid pumping post-throttle temperature are compared to obtain the temperature difference therebetween to determine whether the refrigerant flowing through the liquid pumping flow path still contains liquid refrigerant, and further determine when the liquid pumping state can be exited to restore the normal operation of the components of the air conditioning unit, so as to avoid the long-time refrigerant pumping affecting the heating efficiency of the air conditioning unit.

[0164] It can be understood that, when the temperature difference between the liquid pumping pre-throttle temperature and the liquid pumping post-throttle temperature is greater than or equal to a preset temperature difference threshold, it can be determined that the refrigerant flowing through the liquid pumping flow path still contains a large amount of liquid refrigerant; and when the temperature difference between the liquid pumping pre-throttle temperature and the liquid pumping post-throttle temperature is less than the preset temperature difference threshold, it can be determined that the refrigerant flowing through the liquid pumping flow path contains less liquid refrigerant. The value of the preset temperature difference threshold can be obtained in advance according to the technical specifications and technical requirements of the liquid pumping throttle valve, as long as the state of the refrigerant flowing through the liquid pumping flow path can be determined. In the embodiment of the present application, the preset temperature difference threshold can be valued between 3-8℃.

[0165] In addition, when the liquid pumping flow path is turned on, the opening degree of the liquid pumping throttle valve can be adjusted to an initial opening degree value. The initial opening degree value can be set according to actual needs. In order to avoid too large causing system shock and too small leading to insignificant liquid pumping effect, the initial opening degree value corresponding to the liquid pumping throttle valve is valued between 30%-50% in the embodiment.

[0166] It can be understood that, when the refrigerant flowing through the liquid pumping flow path contains less liquid refrigerant and the suction superheat degree also indicates that the gas refrigerant temperature is increased, it can be determined that there is no suction liquid carrying phenomenon, and the liquid pumping control can be exited to restore the normal operation of the air conditioning unit.

[0167] Specifically, when it is determined that there is no suction liquid carrying phenomenon, the liquid pumping flow path can be turned off, the liquid pumping state can be exited, and the refrigerant pumping at the position of the outlet pipe of the fin heat exchanger can be stopped, so as to avoid the long-time refrigerant pumping affecting the heating efficiency of the air conditioning unit.

[0168] Further, turning off the liquid pumping flow path can be to control the on-off device arranged on the liquid pumping flow path to stop running and stop delivering the refrigerant at the position of the outlet pipe of the fin heat exchanger to the flash evaporator.

[0169] In an exemplary embodiment, referring to Figure 3 , a motive flow path b is arranged between the compressor 1 and the flash evaporator 4, the motive flow path b is provided with an ejector 8, and the liquid pumping flow path a flows into the flash evaporator 4 through the ejector 8.

[0170] It is understandable that, since the flash evaporator 4 is at the medium-pressure end and the finned heat exchanger 6 is at the low-pressure end, the refrigerant on the finned heat exchanger side cannot flow into the flash evaporator side on its own, requiring additional auxiliary power. In this embodiment, since the exhaust port of the compressor 1 is at the high-pressure end, it is considered that an ejector power flow path b can be added from the exhaust port of the compressor 1 to guide the refrigerant to the flash evaporator 4, and then the liquid extraction flow path a can be merged into the ejector power flow path b, so that the ejector power flow path b can provide power for the liquid extraction flow path a to flow into the flash evaporator 4.

[0171] For example, the ejector power flow path b can be implemented by ejector 8.

[0172] It is understandable that the ejector 8 can use a high-speed, high-energy flow (liquid flow, gas flow, or other material flow) to eject another low-speed, low-energy flow. Specifically, the primary fluid is injected into the mixing chamber at a high speed through a converging nozzle, forming a jet that generates entrainment flow, thereby creating a negative pressure zone in the mixing chamber. The fluid to be pumped is drawn into the mixing chamber for mixing. Subsequently, the mixed fluid enters the diffuser chamber, where the pressure increases due to the decrease in flow velocity. At the outlet of the diffuser chamber, the pressure of the mixed fluid is higher than the pressure of the ejected fluid entering the mixing chamber. The mixed fluid finally flows out after being silenced and purified in the silencing chamber.

[0173] In this embodiment, since the ejector 8 has no moving mechanical parts and is not limited by friction, lubrication, or vibration, compared to providing power through a booster pump, it can achieve the desired flow while avoiding additional energy consumption of the air conditioning unit. Simultaneously, directing the gaseous refrigerant from the compressor 1 to the flash evaporator 4 also enhances the gas supply effect to the flash evaporator 4, resulting in a more optimal operating state for the air conditioning unit.

[0174] In one exemplary embodiment, refer to Figure 3 The liquid extraction flow path a is also equipped with a first solenoid valve 11 and a check valve 10, and the ejector power flow path b is also equipped with a second solenoid valve 7. Both the first solenoid valve 11 and the second solenoid valve 7 are connected to the controller. The first solenoid valve 11 is used to open or close the liquid extraction flow path a under the control of the controller, and the second solenoid valve 7 is used to open or close the ejector power flow path b under the control of the controller.

[0175] The solution provided by this air conditioning component is similar to the solution described in the above-mentioned air conditioning control method. Therefore, the specific limitations of the one or more air conditioning unit embodiments provided above can be found in the limitations of the air conditioning unit control method above, and will not be repeated here.

[0176] The following is a process Figure 10 The flowchart shown is for entering the liquid extraction control process, and the process is as follows: Figure 11 Taking the exit control flowchart shown below as an example, for Figure 3 The principle of the liquid extraction process of the air conditioning unit shown is explained below:

[0177] wherein P L is the suction pressure of the compressor, T L is the suction temperature of the compressor, the detection position is located between the compressor 1 and the fin heat exchanger 6. T3 is the temperature after the flash evaporator throttle valve 3 (on the 3-4 flow path), T 9前 is the temperature before the liquid extraction throttle valve 9 (on the 8-9 flow path), T 9后 is the temperature after the liquid extraction throttle valve 9 (on the 9-4 flow path), A is the suction superheat limit value (preset temperature threshold), and B is the throttling temperature difference limit value (preset temperature difference threshold).

[0178] wherein the conventional heating flow path is: compressor 1→hot water heat exchanger 2→flash evaporator throttle valve 3→flash evaporator 4→system throttle valve 5→fin heat exchanger 6→compressor 1. The liquid extraction flow path a is: fin heat exchanger 6→one-way valve 10→solenoid valve 11→ejector 8→liquid extraction throttle valve 9→flash evaporator 4. The ejector power flow path b is: compressor 1→solenoid valve 7→ejector 8→liquid extraction throttle valve 9→flash evaporator 4.

[0179] Referring to Figure 10 , in the conventional operation process of the air conditioning unit, the solenoid valve 7, the solenoid valve 11 and the liquid extraction throttle valve 9 are all in a closed state. The temperature T L and the pressure P L of the suction of the compressor are detected synchronously in the process, and the corresponding saturation temperature of the pressure P L is calculated, to determine whether (T L -(P L corresponding saturation temperature) ≥ A. Wherein T L -(P L corresponding saturation temperature) corresponds to the suction superheat of the compressor. When the suction superheat is negative, it indicates that the compressor has suction liquid carrying. Therefore, the value of A can be set to 0~-1℃.

[0180] When it is detected that the compressor has suction liquid carrying, the solenoid valve 7 and the solenoid valve 11 are opened synchronously, and the liquid extraction throttle valve 9 is opened to an initial opening value. The initial opening value can be set artificially according to the actual situation. In order to avoid excessive opening causing system shock and too small opening leading to insignificant effect, the initial opening value is usually set to 30%~50%. In the conventional operation process, the flash evaporator 4 is at the medium pressure end, and the fin heat exchanger 6 is at the low pressure end. The low pressure cannot flow into the medium pressure by itself. At this time, the ejector 8 needs to be added to provide power to make the low pressure end refrigerant effectively enter the medium pressure end from the high pressure exhaust end.

[0181] The temperature T3 after the flash evaporator throttle valve 3 and the temperature T 9后 after the liquid extraction throttle valve 9 are compared, to determine whether the liquid extraction will affect the flashing of the flash evaporator. When T 9后When T3, the temperature of the refrigerant supplementing into the flash tank will affect the flash effect, so the opening of the suction throttling valve 9 is reduced to strengthen the throttling effect. 9后 When T3, there is no need to adjust. 9后 When <T3, the flash amount in the flash tank is too large and the amount of supplementing gas is too much, which will increase the load of the compressor and easily trigger the overload protection. In this case, the opening of the suction throttling valve 9 is increased to increase the temperature after throttling and reduce the evaporation amount.

[0182] Because the liquid level in the flash tank is too high, the flash effect will be seriously affected, and if the liquid level is too low, the gaseous refrigerant will directly rush to the system throttling valve 5, causing the main throttling to be not smooth. Therefore, the liquid level in the flash tank needs to be detected after the suction throttling valve 9 is adjusted each time. The setpoint liquid level in the flash tank (the preset liquid level threshold, usually set between 1 / 3 and 2 / 3) is set in advance, and when the liquid level reaches the setpoint liquid level, the opening of the flash tank throttling valve 3 and the suction throttling valve 9 is reduced to prevent the liquid level in the flash tank from being too high.

[0183] Then, it is judged again whether T L - (P L , the corresponding saturation temperature) is ≥A. If yes, it indicates that the suction effect is effective and the suction superheat is improved, and the current operation is continued. If still <A, it indicates that the liquid suction is still serious, and the flash tank throttling valve 3 and the system throttling valve 5 are reduced to reduce the refrigerant amount flowing into 6, while the liquid suction state is kept unchanged.

[0184] Referring to Figure 11 , the temperature T 9前 and T 9后 before and after the suction throttling valve 9, the temperature T L and the pressure P L of the suction port of the compressor are continuously detected during the liquid suction operation of the unit.

[0185] Because the normal liquid refrigerant throttling through the suction throttling valve will produce a very obvious temperature difference, but the temperature difference of the gaseous refrigerant throttling is not obvious, so the state of the refrigerant passing through the suction throttling valve 9 can be judged. It is judged whether the temperature difference (T 9前 -T 9后 ) before and after the suction throttling valve 9 is ≥B (usually set as 3-8℃). When (T 9前 -T 9后 ) ≥B, it is considered that the throttling effect is strong and a large amount of refrigerant still passes through, so the current state is maintained. If (T 9前 -T 9后 ) <B, it is determined that the liquid refrigerant in the finned heat exchanger 6 is relatively small, so the next adjustment can be performed to quickly end the liquid suction.

[0186] If the liquid level in the flash tank 4 reaches the specified position, the current state is maintained without adjustment, and if the liquid level does not reach the specified position, the liquid pumping can be further adjusted to speed up the pumping. If T 9后 If T 9后 If T

[0187] When the liquid pumping throttle valve 9 is quickly opened, it is determined whether (T 9前 -T 9后 ) < B and (T L - (P L The corresponding saturation temperature) is greater than or equal to A (the temperature difference is satisfied and the suction gas superheat is positive, which indicates that the liquid refrigerant in the fin heat exchanger has been basically exhausted, and the suction gas does not carry liquid), when the condition is satisfied, the electromagnetic valve 7, the electromagnetic valve 11 and the liquid pumping throttle valve 9 are closed to exit the liquid pumping control; if the condition is not satisfied, the liquid pumping is continued.

[0188] In the embodiment, the newly developed liquid pumping flow path is used to pump the liquid in the fin heat exchanger gas pipe to the flash tank by using the exhaust gas injection, to solve the problem of liquid-carrying suction gas, and to simultaneously enhance the air supplement effect, so that the operation state of the unit reaches an optimal state. The suction gas superheat, the state before and after the liquid pumping throttling, and the liquid level of the flash tank are detected to determine when to enter and exit the liquid pumping, and to control the opening and closing of the injection. The temperature before and after the liquid pumping throttle valve and the temperature state after the flash tank throttling are detected and compared to control the opening of the liquid pumping throttle valve.

[0189] Based on the same inventive concept, the embodiment of the present application also provides an air conditioning unit control device for implementing the air conditioning unit control method described above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more air conditioning unit control device embodiments provided below can be referred to the limitations of the air conditioning unit control method in the above, which will not be repeated here.

[0190] In an exemplary embodiment, as Figure 12 shown, an air conditioning unit control device is provided, which is applied to an air conditioning unit in which a flash tank, a fin heat exchanger and a compressor are connected in sequence, and a liquid pumping flow path is arranged between the fin heat exchanger and the flash tank. Specifically, it includes a determination module, a conduction module, a judgment module and a shutdown module, wherein:

[0191] The determination module 102 is used to continuously determine the compressor suction gas superheat in the operation of the air conditioning unit.

[0192] The conduction module 104 is used to conduct the liquid pumping flow path to transport the liquid refrigerant in the fin heat exchanger to the flash tank when it is determined that there is liquid-carrying suction gas according to the compressor suction gas superheat.

[0193] A judging module 106 is configured to judge the state of the refrigerant flowing through the liquid pumping flow path according to the temperature before liquid throttling and the temperature after liquid throttling. The temperature before liquid throttling is the temperature before the liquid throttling valve, and the temperature after liquid throttling is the temperature after the liquid throttling valve.

[0194] A turning-off module 108 is configured to turn off the liquid pumping flow path when it is determined that there is no liquid entrainment according to the state of the refrigerant flowing through the liquid pumping flow path and the suction superheat.

[0195] In an exemplary embodiment, a motive flow path is arranged between the compressor and the flash tank, and the liquid pumping flow path merges into the flash tank through the motive flow path.

[0196] The conducting module 104 is further configured to conduct the motive flow path to assist in transporting the liquid refrigerant in the finned heat exchanger to the flash tank when it is determined that there is liquid entrainment according to the suction superheat of the compressor.

[0197] The turning-off module 108 is further configured to turn off the motive flow path when it is determined that there is no liquid entrainment according to the state of the refrigerant flowing through the liquid pumping flow path and the suction superheat.

[0198] In an exemplary embodiment, the air conditioning unit control device further comprises an adjusting module,

[0199] The adjusting module is configured to reduce the opening of the liquid throttling valve when the temperature after liquid throttling is greater than the temperature after throttling of the flash tank. The temperature after throttling of the flash tank is the temperature after the throttling valve of the flash tank. The throttling valve of the flash tank is located in the conventional heating flow path of the air conditioning unit. When the temperature after liquid throttling is equal to the temperature after throttling of the flash tank, the current state is maintained. When the temperature after liquid throttling is less than the temperature after throttling of the flash tank, the opening of the liquid throttling valve is increased.

[0200] In an exemplary embodiment,

[0201] The adjusting module is configured to continuously detect the liquid level of the flash tank, and simultaneously reduce the openings of the throttling valve of the flash tank and the liquid throttling valve when the liquid level of the flash tank reaches a preset reference liquid level.

[0202] In an exemplary embodiment,

[0203] The adjusting module is further configured to simultaneously reduce the openings of the throttling valve of the flash tank and the system throttling valve when it is determined that there is still liquid entrainment according to the suction superheat of the compressor. The system throttling valve is located in the conventional heating flow path.

[0204] In an exemplary embodiment,

[0205] The determining module 102 is configured to continuously detect the suction end temperature and the suction end pressure of the compressor, determine the corresponding suction end saturation temperature according to the suction end pressure, and determine the suction superheat of the compressor according to the suction end temperature and the suction end saturation temperature.

[0206] In an exemplary embodiment,

[0207] The conducting module 104 is further configured to, in the case that the suction superheat of the compressor is negative, determine that there is suction liquid entrainment, conduct the liquid refrigerant in the fin heat exchanger to the flash tank, and deliver the liquid refrigerant to the flash tank.

[0208] In an exemplary embodiment,

[0209] The judging module 106 is further configured to determine the temperature difference before and after the liquid suction throttling according to the temperature before and after the liquid suction throttling, determine that the state of the refrigerant flowing through the liquid suction flow path is that there is a large amount of liquid refrigerant in the case that the temperature difference before and after the liquid suction throttling is greater than or equal to a preset temperature difference threshold, and determine that the state of the refrigerant flowing through the liquid suction flow path is that there is less liquid refrigerant in the case that the temperature difference before and after the liquid suction throttling is less than the preset temperature difference threshold.

[0210] In an exemplary embodiment,

[0211] The shutting-off module 108 is further configured to, in the case that the state of the refrigerant flowing through the liquid suction flow path is that there is less liquid refrigerant and the suction superheat is positive, determine that there is no suction liquid entrainment, and shut off the liquid suction flow path.

[0212] In an exemplary embodiment,

[0213] The adjusting module is further configured to, in the case that the state of the refrigerant flowing through the liquid suction throttling valve is that there is less liquid refrigerant and the liquid level of the flash tank reaches a preset calibration liquid level, keep the current state running, and in the case that the state of the refrigerant flowing through the liquid suction throttling valve is that there is less liquid refrigerant and the liquid level of the flash tank does not reach the preset calibration liquid level, increase the opening degree of the liquid suction throttling valve.

[0214] In an exemplary embodiment,

[0215] The adjusting module is configured to, in the case that the liquid level of the flash tank does not reach the preset calibration liquid level and the temperature after the liquid suction throttling is less than the temperature after the flash tank throttling, increase the opening degree of the liquid suction throttling valve by a preset multiple.

[0216] The above various modules in the air conditioning unit control device can be realized by software, hardware, or a combination thereof. The above various modules can be embedded in or independent of a processor in a computer device in a hardware form, or can be stored in a memory in a computer device in a software form, so as to be called and executed by a processor to perform the operations corresponding to the above various modules.

[0217] In an exemplary embodiment, a computer device, which can be a server, is provided, and an internal structure diagram of the computer device can be as shown in FIG. 1. Figure 13 The computer device includes a processor, a memory, an input / output interface (I / O), and a communication interface. The processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for running the operating system and the computer program in the non-volatile storage medium. The database of the computer device is configured to store data such as suction superheat of a compressor and operating parameters of components of an air conditioning unit. The input / output interface of the computer device is configured to exchange information between the processor and external devices. The communication interface of the computer device is configured to communicate with terminals outside through a network connection. The computer program is executed by the processor to implement an air conditioning unit control method.

[0218] Those skilled in the art can understand that Figure 13 The structure shown in FIG. 1 is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0219] In an exemplary embodiment, a computer device is provided, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the air conditioning unit control method described above.

[0220] In an exemplary embodiment, a computer readable storage medium is provided, which stores a computer program. The computer program is executed by a processor to implement the steps of the air conditioning control method described above.

[0221] In an exemplary embodiment, a computer program product is provided, which includes a computer program. The computer program is executed by a processor to implement the steps of the air conditioning control method described above.

[0222] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or authorized by all parties, and the collection, use, and processing of related data need to comply with relevant regulations.

[0223] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned embodiment methods. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. The non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. The volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, the RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., without being limited thereto.

[0224] The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0225] The above-described embodiments are merely illustrative of several embodiments of the present application, and the description is relatively specific and detailed, but should not be understood as a limitation on the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A method for controlling an air conditioning unit, characterized in that, The air conditioning unit includes a flash evaporator, a finned heat exchanger, and a compressor connected in sequence. A liquid extraction flow path is provided between the finned heat exchanger and the flash evaporator. The method includes: Continuously determine the compressor suction superheat during air conditioning unit operation; If it is determined that there is liquid carryover in the suction gas based on the superheat of the compressor suction gas, the liquid pumping flow path is opened to transport the liquid refrigerant in the finned heat exchanger to the flash evaporator. If the temperature after liquid extraction throttling is higher than the temperature after flash evaporator throttling, reduce the opening of the liquid extraction throttling valve; if the temperature after liquid extraction throttling is equal to the temperature after flash evaporator throttling, maintain the current operating state; if the temperature after liquid extraction throttling is lower than the temperature after flash evaporator throttling, increase the opening of the liquid extraction throttling valve; the temperature after flash evaporator throttling is the temperature after the flash evaporator throttling valve, the flash evaporator throttling valve is located in the conventional heating flow path of the air conditioning unit, the temperature after liquid extraction throttling is the temperature after the liquid extraction throttling valve, and the liquid extraction throttling valve is located in the liquid extraction flow path; The state of the refrigerant flowing through the liquid extraction path is determined based on the temperature before liquid extraction and the temperature after liquid extraction and throttling, wherein the temperature before liquid extraction and throttling is the temperature before the liquid extraction and throttling valve. If it is determined that there is no liquid carryover during suction based on the state of the refrigerant flowing through the liquid extraction path and the suction superheat, the liquid extraction path shall be shut off.

2. The method according to claim 1, characterized in that, An ejector power flow path is provided between the compressor and the flash generator, and the liquid extraction flow path flows into the flash generator through the ejector power flow path; The method further includes: If it is determined that there is liquid carryover in the suction gas based on the superheat of the compressor suction gas, the ejector power flow path is opened to assist in transporting the liquid refrigerant in the finned heat exchanger to the flash evaporator. If no liquid is carried in the suction flow path when it is determined that there is no suction liquid based on the state of the refrigerant flowing through the liquid extraction path and the suction superheat, the ejector power flow path is shut off.

3. The method according to claim 1, characterized in that, After adjusting the opening of the liquid extraction throttle valve, the method further includes: Continuously monitor the liquid level in the flash evaporator; When the liquid level in the flash evaporator reaches the preset calibrated liquid level, the opening of the flash evaporator throttle valve and the liquid extraction throttle valve are simultaneously reduced.

4. The method according to claim 1, characterized in that, The method further includes: If, based on the superheat of the compressor intake, it is determined that there is still liquid carryover in the intake, the opening of the flash evaporator throttle valve and the system throttle valve are simultaneously reduced, with the system throttle valve located in the conventional heating flow path.

5. The method according to claim 1, characterized in that, The continuous determination of compressor suction superheat during air conditioning unit operation includes: Continuously monitor the compressor's suction end temperature and suction end pressure; The corresponding intake saturation temperature is determined based on the intake pressure. The compressor suction superheat is determined based on the suction end temperature and the suction end saturation temperature.

6. The method according to claim 1, characterized in that, Determining the presence of liquid in the intake air based on the compressor intake superheat includes: if the compressor intake superheat is negative, then it is determined that liquid is present in the intake air.

7. The method according to claim 1, characterized in that, The step of determining the refrigerant state flowing through the liquid extraction path based on the temperature before and after liquid extraction throttling includes: The temperature difference before and after liquid throttling is determined based on the temperature before and after liquid throttling. If the temperature difference before and after the liquid extraction throttling is greater than or equal to a preset temperature difference threshold, the refrigerant flowing through the liquid extraction path is determined to be in a state of having a large amount of liquid refrigerant. If the temperature difference before and after the liquid extraction throttling is less than the preset temperature difference threshold, the refrigerant flowing through the liquid extraction path is determined to be in a state of low liquid refrigerant.

8. The method according to claim 7, characterized in that, Determining whether there is liquid carryover in the suction flow based on the state of the refrigerant flowing through the liquid extraction path and the suction superheat includes: if the state of the refrigerant flowing through the liquid extraction path is that there is relatively little liquid refrigerant and the suction superheat is positive, then it is determined that there is no liquid carryover in the suction flow.

9. The method according to claim 7, characterized in that, If it is determined that the refrigerant flowing through the liquid extraction throttling valve is in a state of low liquid refrigerant, the method further includes: If the liquid level in the flash evaporator reaches the preset calibration level, it will continue to operate in the current state. If the liquid level in the flash evaporator does not reach the preset calibrated liquid level, increase the opening of the liquid extraction throttle valve.

10. The method according to claim 9, characterized in that, The step of increasing the opening of the liquid extraction throttle valve when the liquid level in the flash evaporator has not reached the preset calibration level includes: If the temperature after the liquid extraction throttling is lower than the temperature after the flash evaporator throttling, the opening of the liquid extraction throttling valve is increased by a preset multiple.

11. An air conditioning unit control device, characterized in that, The air conditioning unit includes a flash evaporator, a finned heat exchanger, and a compressor connected in sequence. A liquid extraction flow path is provided between the finned heat exchanger and the flash evaporator. The device includes: The determination module is used to continuously determine the compressor suction superheat during the operation of the air conditioning unit; The conduction module is used to conduct the liquid extraction flow path to transport the liquid refrigerant in the finned heat exchanger to the flash evaporator when it is determined that there is liquid carry-in in the suction gas based on the superheat of the compressor suction gas. The adjustment module is used to reduce the opening of the liquid extraction throttling valve when the temperature after liquid extraction throttling is greater than the temperature after flash evaporator throttling; maintain the current operating state when the temperature after liquid extraction throttling is equal to the temperature after flash evaporator throttling; and increase the opening of the liquid extraction throttling valve when the temperature after liquid extraction throttling is less than the temperature after flash evaporator throttling. The temperature after flash evaporator throttling is the temperature after the flash evaporator throttling valve, which is located in the conventional heating flow path of the air conditioning unit. The temperature after liquid extraction throttling is the temperature after the liquid extraction throttling valve, which is located in the liquid extraction flow path. The judgment module is used to determine the state of the refrigerant flowing through the liquid extraction path based on the temperature before liquid extraction and the temperature after liquid extraction and throttling, wherein the temperature before liquid extraction and throttling is the temperature before the liquid extraction and throttling valve. The shut-off module is used to shut off the liquid extraction path when it is determined that there is no liquid carryover during suction based on the state of the refrigerant flowing through the liquid extraction path and the suction superheat.

12. An air conditioning unit, characterized in that, The unit includes a flash evaporator, a finned heat exchanger, and a compressor connected in sequence. A liquid extraction flow path is provided between the finned heat exchanger and the flash evaporator. A liquid extraction throttling valve is provided on the liquid extraction flow path. A flash evaporator throttling valve is provided on the conventional heating flow path of the air conditioning unit. The air conditioning unit further includes a controller and a temperature detection module connected to the controller. The temperature detection module is used to detect the temperature before and after liquid throttling of the liquid extraction throttling valve, and the temperature after flash evaporator throttling of the flash evaporator throttling valve. The controller is used to control the on / off state and opening degree of the liquid extraction flow path according to any one of claims 1 to 10, so as to transport the liquid refrigerant in the finned heat exchanger to the flash evaporator.

13. The air conditioning unit according to claim 12, characterized in that, An ejector power flow path is provided between the compressor and the flash generator, and an ejector is provided on the ejector power flow path. The liquid extraction flow path flows into the flash generator through the ejector.

14. The air conditioning unit according to claim 13, characterized in that, The liquid extraction flow path is also equipped with a first solenoid valve and a check valve, and the ejector power flow path is also equipped with a second solenoid valve. Both the first solenoid valve and the second solenoid valve are connected to the controller. The first solenoid valve is used to open or close the liquid extraction path under the control of the controller, and the second solenoid valve is used to open or close the ejector power path under the control of the controller.

15. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 10.

16. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 10.

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