Gas-liquid separator, air conditioner and control method of air conditioner

Abstract

The invention relates to an air conditioner, particularly provides a gas-liquid separator, an air conditioner and a control method of the air conditioner, and aims to solve the problem of liquid impact of a compressor caused by excessive accumulation of a liquid refrigerant in a gas-liquid separator of an existing air conditioner. In order to achieve the purpose, the gas-liquid separator of the air conditioner comprises a cavity, a heating device and at least one temperature sensor, and the heating device is used for heating liquid in the cavity; the temperature sensors are arranged in the cavity and located above the target liquid level of the cavity so that when the temperature detected by at least one temperature sensor is smaller than the evaporation temperature, the liquid level in the cavity can be located below the target liquid level through heating of the heating device. When the temperature detected by the temperature sensor is smaller than the evaporation temperature, it is proved that the liquid in the gas-liquid separator is too much, at the moment, the heating device needs to be started to enable the liquid in the cavity to be below the target liquid level, and therefore the compressor is prevented from generating liquid impact.

Description

Technical Field

[0001] The present invention relates to the field of air conditioners, and particularly provides a gas-liquid separator, an air conditioner and a control method for the air conditioner. Background Art

[0002] In an air conditioner, the main function of the gas-liquid separator is to separate the mixed gas-liquid refrigerant entering the compressor, ensuring that only gaseous refrigerant enters the compressor, thereby preventing liquid refrigerant from directly entering the compressor and causing liquid hammer phenomenon.

[0003] However, in some scenarios, part of the liquid refrigerant still enters the compressor. For example, when the air conditioner is heating under a relatively low ambient temperature, the heating performance of the air conditioner will decline, resulting in a reduction in the amount of refrigerant required for the entire air conditioner to heat, and most of the refrigerant will exist in the gas-liquid separator in a liquid form. When the operating state of the air conditioner changes drastically, part of the liquid refrigerant may enter the compressor and cause liquid hammer, and further, it will also affect the overall performance of the air conditioner.

[0004] Correspondingly, there is a need in the art for a new gas-liquid separator, air conditioner and control method for the air conditioner to solve the problem that the existing air conditioner is prone to compressor liquid hammer phenomenon. Summary of the Invention

[0005] The present invention aims to solve the above technical problems, that is, to solve the problem that excessive accumulation of liquid refrigerant in the gas-liquid separator of the existing air conditioner causes compressor liquid hammer.

[0006] In a first aspect, the present invention provides a gas-liquid separator for an air conditioner, characterized in that it includes: a cavity; a heating device for heating the liquid in the cavity; at least one temperature sensor disposed in the cavity and above a target liquid level of the cavity, so that when the temperature detected by at least one of the temperature sensors is less than the evaporation temperature, the liquid level in the cavity is below the target liquid level through the heating of the heating device.

[0007] When the air conditioner is in heating operation, it is necessary to ensure that the liquid level in the gas-liquid separator is always below the target liquid level in order to avoid excessive liquid in the gas-liquid separator and cause liquid hammer. The present invention disposes the temperature sensor above the target liquid level of the gas-liquid separator, so that when the liquid in the gas-liquid separator is excessive and exceeds the target liquid level, the temperature sensor will contact the liquid, making the temperature detected by the temperature sensor lower than the evaporation temperature. Therefore, when the temperature detected by the temperature sensor is less than the evaporation temperature, it proves that the liquid in the gas-liquid separator is excessive. At this time, the heating device needs to be turned on to make the liquid in the cavity below the target liquid level, thereby avoiding compressor liquid hammer.

[0008] In the alternative technical solutions of the gas-liquid separator of the above air conditioner, the temperature sensor includes a first temperature sensor, a second temperature sensor, and a third temperature sensor that are sequentially arranged at intervals from bottom to top; and / or the heating device is configured as a heating rod, the heating rod is arranged in the cavity and arranged along the height direction of the cavity; a tube body is sleeved outside the heating rod, and the temperature sensor is arranged on the side wall of the tube body.

[0009] With the above arrangement, the heating device, the tube body, and the temperature sensor can jointly form a module, which is convenient for installation and integration on the gas-liquid separator and reduces the installation complexity. In addition, the liquid level in the gas-liquid separator will change dynamically. The heating rod arranged along the height direction can better adapt to this change. Whether the liquid level is high or low, the heating rod can heat the liquid at different liquid levels. When the liquid level is low, the heating rod part at the lower position can still heat the liquid at the lower liquid level; when the liquid level is high, the entire heating rod can give full play to its role and heat more liquid. Ensure that the liquid can be effectively heated in various liquid level states, and avoid the situation where the heating function fails due to the change of the liquid level.

[0010] On the other hand, the present invention provides an air conditioner, and the air conditioner includes the gas-liquid separator described in any of the above embodiments.

[0011] After the air conditioner has the above gas-liquid separator, the liquid in the cavity of the gas-liquid separator can always be below the target liquid level, thereby avoiding liquid slugging of the compressor and improving the operating efficiency.

[0012] On the other hand, the present invention provides a control method for an air conditioner, characterized in that the air conditioner includes a gas-liquid separator, and the gas-liquid separator includes: a cavity; a heating device for heating the liquid in the cavity; at least one temperature sensor arranged in the cavity and above the target liquid level of the cavity; the control method includes: when the air conditioner is running, obtaining the evaporation temperature; obtaining the temperature detected by the temperature sensor; comparing the magnitudes of the evaporation temperature and the temperature detected by the temperature sensor; when the temperature detected by at least one of the temperature sensors is less than the evaporation temperature, controlling the heating device to heat so that the liquid level in the cavity is below the target liquid level.

[0013] During the operation of the air conditioner, when the temperature detected by at least one temperature sensor is less than the evaporation temperature, it means that the liquid level in the gas-liquid separator has exceeded the target liquid level. In this case, the compressor is prone to liquid slugging. Therefore, by controlling the heating device, the liquid level in the cavity of the gas-liquid separator is below the target liquid level, effectively preventing the compressor from generating liquid slugging due to excessive liquid and ensuring the stable and safe operation of the air conditioner.

[0014] In an alternative technical solution of the control method of the above air conditioner, the temperature sensor includes a first temperature sensor, a second temperature sensor, and a third temperature sensor that are sequentially arranged at intervals from bottom to top. The first temperature sensor is used to detect the first temperature, the second temperature sensor is used to detect the second temperature, and the third temperature sensor is used to detect the third temperature. The step of "when the temperature detected by at least one of the temperature sensors is less than the evaporation temperature, controlling the heating device to heat" further includes: when the second temperature > the evaporation temperature > the first temperature, controlling the heating device to heat for a first preset duration or at a first preset power; when the third temperature > the evaporation temperature > the second temperature, controlling the heating device to heat for a second preset duration or at a second preset power; where the second preset duration is greater than the first preset duration, and the second preset power is greater than the first preset power.

[0015] When the second temperature > the evaporation temperature > the first temperature, it indicates that the liquid level in the gas-liquid separator has reached the position of the first temperature sensor but not the position of the second temperature sensor, that is, the liquid level reaches a liquid level one that exceeds the target liquid level. When the third temperature > the evaporation temperature > the second temperature, it indicates that the liquid level has reached the second temperature sensor but not the position of the third temperature sensor. At this time, the liquid level reaches a liquid level two that is higher than the liquid level one. Since the liquid level two is relatively higher than the liquid level one, when the liquid level reaches the liquid level two, compared with when the liquid level reaches the liquid level one, the heating device heats for a longer duration or at a higher power. It can ensure that in both the case of the liquid level one and the liquid level two, through the reasonable operation of the heating device, the liquid level can be accurately and effectively reduced below the target liquid level, ensuring the stable and safe operation of the gas-liquid separator and even the entire air conditioner, and avoiding failures such as compressor liquid slug caused by out-of-control liquid level.

[0016] In an alternative technical solution of the control method of the above air conditioner, the step of "when the temperature detected by at least one of the temperature sensors is less than the evaporation temperature, controlling the heating device to heat" further includes: when the evaporation temperature > the third temperature, controlling the heating device to heat for a third preset duration or at a third preset power; where the third preset duration is greater than the second preset duration, and the third preset power is greater than the second preset power.

[0017] When the evaporation temperature > the third temperature, it indicates that the gas-liquid separator has risen to the position of the third temperature sensor or even higher. Therefore, control the heating device to heat for a longer duration than when the liquid level is at the liquid level two, or heat at a higher third preset power to ensure that the liquid level is quickly pulled back below the target liquid level.

[0018] In an alternative technical solution of the above air conditioner control method, the step of "when the third temperature > the evaporation temperature > the second temperature, controlling the heating device to heat for a second preset duration or at a second preset power" further includes: when the third temperature > the evaporation temperature > the second temperature and the first temperature, controlling the heating device to heat for a second preset duration or at a second preset power.

[0019] Under normal circumstances, it can be determined that the liquid level height has reached the position where the second temperature sensor is located only when the evaporation temperature is greater than the second temperature. During actual operation, the temperature sensor may fail due to long-term use, environmental interference, or its own quality problems. Once a certain temperature sensor fails and outputs an incorrect signal, if the liquid level position is determined only based on the comparison of the single evaporation temperature and the second temperature, it may lead to misjudgment. In the present invention, when the evaporation temperature is greater than both the first temperature and the second temperature, it is further determined that the liquid level of the gas-liquid separator has reached the position where the second temperature sensor is located, and then the heating device is controlled to heat for a second preset duration or at a second preset power. By adopting a dual guarantee mechanism, it can effectively avoid the incorrect judgment caused by the failure of the temperature sensor, and greatly improve the accuracy and reliability of the air conditioner in liquid level monitoring and control.

[0020] In an alternative technical solution of the above air conditioner control method, the step of "when the evaporation temperature > the third temperature, controlling the heating device to heat for a third preset duration or at a third preset power" further includes: when the evaporation temperature > the first temperature, the second temperature, and the third temperature, controlling the heating device to heat for a third preset duration or at a third preset power.

[0021] Similarly, when the evaporation temperature > the first temperature, the second temperature, and the third temperature, the heating device is controlled to heat for a third preset duration or at a third preset power. It can further avoid the incorrect judgment caused by the failure of the temperature sensor, and greatly improve the accuracy and reliability of the air conditioner in liquid level monitoring and control.

[0022] In an alternative technical solution of the above air conditioner control method, the control method further includes: when operating in the heating mode, before reaching the frosting condition, controlling the heating device to heat.

[0023] Controlling the heating device to heat before reaching the frosting condition can heat the liquid refrigerant in the gas-liquid separator, increase the circulation amount of the refrigerant in the air conditioner, thereby improving the heating capacity, and at the same time can also reduce the frosting amount.

[0024] In an alternative technical solution of the control method of the above air conditioner, the step of "controlling the heating device to heat before the frosting condition is reached" further includes: obtaining the pipe temperature of the outdoor heat exchanger; when the pipe temperature is less than or equal to a preset temperature, controlling the heating device to heat; and / or when the last defrosting operation time / the time interval from the end of the last defrosting to the current time is greater than or equal to a preset percentage, controlling the heating device to heat.

[0025] When the pipe temperature is less than or equal to the preset temperature, it indicates that the outdoor heat exchanger has frosted or is about to frost. At this time, controlling the heating device to heat can increase the refrigerant circulation volume of the air conditioner, thereby improving the heating capacity and reducing the frosting amount at the same time. When the last defrosting operation time / the time interval from the end of the last defrosting to the current time is greater than or equal to the preset percentage, it means that the time interval after the last defrosting is short while the defrosting time is long, indicating that the frost layer accumulates rapidly. In this case, the surface of the outdoor heat exchanger is prone to rapid frosting, resulting in a decrease in heat exchange efficiency. By starting the heating device at this time, the frost layer can be prevented from getting thicker, ensuring that the system can continuously maintain good heating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The following describes the preferred embodiments of the present invention with reference to the drawings, in which:

[0027] Figure 1 is a schematic structural diagram of the air conditioner of the present invention;

[0028] Figure 2 is a schematic structural diagram of the gas-liquid separator of the air conditioner of the present invention;

[0029] Figure 3 is a flowchart of the control method of the air conditioner of the present invention.

[0030] DESCRIPTION OF THE REFERENCE NUMERALS

[0031] 1 - Compressor; 2 - Indoor heat exchanger; 3 - Throttling element; 4 - Outdoor heat exchanger; 5 - Reversing valve; 6 - Gas-liquid separator; 61 - Cavity; 62 - Heating device; 63 - First temperature sensor; 64 - Second temperature sensor; 65 - Third temperature sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following describes the preferred embodiments of the present invention with reference to the drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present invention and are not intended to limit the protection scope of the present invention. Those skilled in the art can make adjustments according to needs to adapt to specific application scenarios.

[0033] It should be noted that in the description of the present invention, the terms "upper" and "lower" refer to the upper and lower parts of the gas-liquid separator based on the height direction in the use state. In addition, it should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0034] The present invention provides an air conditioner. As Figure 1 shown, the air conditioner includes a compressor 1, an indoor heat exchanger 2, a throttling element 3, and an outdoor heat exchanger 4 that are sequentially connected and form a closed loop. The air conditioner also includes a four-way reversing valve 5 and a gas-liquid separator 6. In this case, the compressor 1 forms a closed loop with the indoor heat exchanger 2, the throttling element 3, and the outdoor heat exchanger 4 through the reversing valve 5. The reversing valve 5 includes an inlet, an outlet, a first port, and a second port. The inlet is connected to the exhaust port of the compressor 1 through a first refrigerant pipe, the outlet is connected to the suction port of the compressor 1 through a second refrigerant pipe, the first port is connected to the gas port of the indoor heat exchanger 2, and the second port is connected to the gas port of the outdoor heat exchanger 4. The gas-liquid separator 6 is provided on the second refrigerant pipe. When the air conditioner operates in heating mode, the first port is connected to the inlet, the second port is connected to the outlet, and the refrigerant discharged from the compressor 1 sequentially flows through the inlet and the first port of the reversing valve 5, the indoor heat exchanger 2, the throttling element 3, the outdoor heat exchanger 4, the second port and the outlet of the reversing valve 5, the gas-liquid separator 6, and returns to the compressor 1. When the air conditioner operates in cooling mode, the first port is connected to the outlet, the second port is connected to the inlet, and the refrigerant discharged from the compressor 1 sequentially flows through the inlet and the second port of the reversing valve 5, the outdoor heat exchanger 4, the throttling element 3, the indoor heat exchanger 2, the first port and the outlet of the reversing valve 5, the gas-liquid separator 6, and returns to the compressor 1. Of course, the present invention can also omit the setting of the reversing valve 5, that is, the air conditioner includes a compressor 1, an indoor heat exchanger 2, a throttling element 3, an outdoor heat exchanger 4, and a gas-liquid separator 6 that are sequentially connected and form a closed loop. The refrigerant discharged from the compressor 1 sequentially flows through the indoor heat exchanger 2, the throttling element 3, the outdoor heat exchanger 4, the gas-liquid separator 6, and returns to the compressor 1. The above throttling element 3 can be an electronic expansion valve or a capillary tube, etc.

[0035] As Figure 2As shown, the gas-liquid separator 6 of the present invention includes a cavity 61, a heating device 62, and at least one temperature sensor. The heating device 62 is used to heat the liquid in the cavity 61. The temperature sensor is disposed in the cavity 61 and above the target liquid level of the cavity 61, so that when the temperature detected by the at least one temperature sensor is less than the evaporation temperature, the liquid level in the cavity 61 can be made below the target liquid level through the heating of the heating device 62.

[0036] During the operation of the air conditioner, it is necessary to ensure that the liquid level in the gas-liquid separator 6 is always below the target liquid level to avoid liquid hammer caused by excessive liquid in the gas-liquid separator 6. The target liquid level can be determined through experiments or empirical formulas, etc. The target liquid level should be able to avoid the liquid hammer phenomenon of the compressor 1. For example, record the liquid level when the liquid hammer phenomenon occurs in the air conditioner compressor 1, and determine the average value through multiple repeated experiments. It can also refer to the requirements for liquid level control in relevant product standards and specifications in the air conditioner industry, and comprehensively determine it in combination with the special requirements of the product, such as special low-temperature environment applications, etc.

[0037] In the present invention, the temperature sensor is installed above the target liquid level of the gas-liquid separator 6. During the operation of the air conditioner, once the liquid in the gas-liquid separator 6 is excessive and exceeds the target liquid level, the temperature sensor will come into contact with the liquid. Due to the temperature characteristics, the temperature detected by the temperature sensor will be lower than the evaporation temperature. Based on this principle, when the temperature monitored by the temperature sensor is lower than the evaporation temperature, it indicates that the liquid in the gas-liquid separator 6 is excessive. In this case, the heating device 62 will be turned on, and the liquid in the cavity 61 will be reduced by heating, so that it falls below the target liquid level, thereby effectively preventing the compressor 1 from generating liquid hammer due to excessive liquid and ensuring the stable and safe operation of the air conditioner.

[0038] As a possible implementation manner, the heating device 62 is configured as a heating rod. The heating rod is disposed in the cavity 61 and arranged along the height direction of the cavity 61. A tube body is sleeved outside the heating rod, and the temperature sensor is disposed on the side wall of the tube body. The above setting method can form a module together with the heating device 62, the tube body, and the temperature sensor, which is convenient for installation and integration on the gas-liquid separator 6 and reduces the installation complexity. In addition, the liquid level in the gas-liquid separator 6 will change dynamically. The heating rod arranged along the height direction can better adapt to this change. Whether the liquid level is high or low, the heating rod can heat the liquid at different liquid levels. When the liquid level is low, the heating rod part at the lower position can still heat the liquid at the lower liquid level; when the liquid level is high, the entire heating rod can fully play its role and heat more liquid. Ensure that the liquid can be effectively heated in various liquid level states and avoid the situation where the heating function fails due to liquid level changes.

[0039] Among them, the pipe body can be a blind pipe, and the heating rod is arranged in the blind pipe. It should be noted that although the heating device 62 of the present invention is introduced by taking the heating rod as an example, this is not intended to limit the protection scope of the present invention. As long as it can heat the liquid in the gas-liquid separator 6, its setting method can be adjusted. For example, the heating device 62 is a heating wire coil, which is coiled on a special bracket and placed in the cavity 61 to increase the contact area with the liquid; or a heating plate array is used, and multiple small heating plates are distributed at different heights and positions, and can be independently controlled for precise heating. For the installation of the temperature sensor on the pipe body, as long as the temperature sensor can be installed on the side wall of the pipe body. The embedded method can be adopted, a groove is opened on the side wall of the pipe body to embed the temperature sensor and fixed and sealed with a sealing material; a ferrule can also be set on the pipe body to fix the temperature sensor on the ferrule; there is also a bonding installation method, and the temperature sensor is firmly pasted on the surface of the pipe body.

[0040] In addition, although the present invention is introduced by setting the temperature sensor on the side wall of the pipe body, this is not intended to limit the protection scope of the present invention, and its setting method can be adjusted. For example, the temperature sensor is set on the inner wall of the cavity 61 of the gas-liquid separator 6, etc. These adjustments do not deviate from the principle of the present invention and are all within the protection scope of the present invention.

[0041] As a possible implementation manner, the temperature sensor includes a first temperature sensor 63, a second temperature sensor 64, and a third temperature sensor 65 that are sequentially arranged at intervals from bottom to top. Thus, the temperature at different heights of the gas-liquid separator 6 can be detected. When the liquid rises to the temperature sensors at different positions, the temperature measured by the temperature sensor at the corresponding position will be lower than the evaporation temperature. By comparing the differences between the temperatures measured by the sensors at each height and the evaporation temperature, the liquid level height in the gas-liquid separator 6 can be accurately obtained. The heating device 62 is controlled to heat precisely according to the liquid level height, so that the liquid level height is always stable below the target liquid level, effectively avoiding liquid slugging of the compressor 1 caused by abnormal liquid level.

[0042] Next, the control method of the air conditioner of the present invention will be introduced. As Figure 3 shown, the control method of the present invention includes the following steps:

[0043] Step S100: When the air conditioner is running, obtain the evaporation temperature.

[0044] Specifically, when the air conditioner is operating in the cooling or heating mode, the evaporation temperature can be obtained. The evaporation temperature can be obtained by any existing or future possible method. For example, a temperature sensor can be installed at the outlet pipe of the heat exchanger acting as the evaporator, and the temperature detected by this temperature sensor is used as the evaporation temperature. Or the evaporation temperature can be determined by the suction pressure. There is a corresponding relationship between the suction pressure of a specific refrigerant and the evaporation temperature, which can be found with the help of a refrigerant thermodynamic property table or an empirical formula. For example, for refrigerant R22, when the suction pressure reaches 0.5 MPa, referring to the property table, the evaporation temperature is about 5°C. It is also possible to calculate the logarithmic mean temperature difference based on the refrigeration capacity, the heat transfer coefficient of the evaporator, and the heat transfer area, and then inversely deduce the evaporation temperature in combination with the refrigerant temperature at the outlet of the condenser, etc.

[0045] Step S200: Obtain the temperature detected by the temperature sensor.

[0046] The temperature detected by each temperature sensor can be obtained. For the convenience of description, the temperature detected by the first temperature sensor is called the first temperature, the temperature detected by the second temperature sensor is called the second temperature, and the temperature detected by the third temperature sensor is called the third temperature.

[0047] Step S300: Compare the magnitudes of the evaporation temperature and the temperature detected by the temperature sensor.

[0048] The magnitudes of the evaporation temperature and the temperature detected by each temperature sensor can be compared.

[0049] Step S400: When the temperature detected by at least one temperature sensor is less than the evaporation temperature, control the heating device to heat so that the liquid level in the cavity is below the target liquid level.

[0050] During the operation of the air conditioner, when the temperature detected by at least one temperature sensor is less than the evaporation temperature, it means that the liquid level in the gas-liquid separator has exceeded the target liquid level. In this case, the compressor is prone to liquid slugging. Therefore, by controlling the heating device, the liquid level in the cavity of the gas-liquid separator is kept below the target liquid level, effectively preventing the compressor from experiencing liquid slugging due to excessive liquid and ensuring the stable and safe operation of the air conditioner.

[0051] As a possible implementation manner, step S400 further includes:

[0052] When the second temperature > evaporation temperature > the first temperature, control the heating device to heat for a first preset duration; when the third temperature > evaporation temperature > the second temperature, control the heating device to heat for a second preset duration. Here, the second preset duration is greater than the first preset duration.

[0053] When the second temperature > evaporation temperature > the first temperature, it indicates that the liquid level in the gas-liquid separator has reached the position of the first temperature sensor but not the position of the second temperature sensor, that is, the liquid level has reached level one which is higher than the target liquid level. When the third temperature > evaporation temperature > the second temperature, it indicates that the liquid level has reached the second temperature sensor but not the position of the third temperature sensor. At this time, the liquid level has reached level two which is higher than level one. Since level two is higher than level one, when the liquid level reaches level two, compared with when the liquid level reaches level one, the heating duration of the heating device is longer. It can ensure that in both the case of level one and level two, through the reasonable operation of the heating device, the liquid level can be accurately and effectively reduced below the target liquid level, ensuring the stable and safe operation of the gas-liquid separator and even the entire air conditioner, and avoiding faults such as compressor liquid slug caused by out-of-control liquid level.

[0054] Further, when the evaporation temperature > the third temperature, the heating device is controlled to heat for a third preset duration. Among them, the third preset duration is greater than the second preset duration. When the evaporation temperature > the third temperature, it indicates that the gas-liquid separator has risen to the position of the third temperature sensor or even higher. Therefore, the heating duration of the heating device is controlled to be greater than the heating duration when the liquid level is at level two, ensuring that the liquid level is quickly pulled back below the target liquid level.

[0055] Among them, the values of the first preset duration, the second preset duration, and the third preset duration are not fixed and can be flexibly adjusted according to various factors. For example, the heating duration is related to the volume of the gas-liquid separator. A gas-liquid separator with a large volume can hold more liquid, and the liquid level changes relatively slowly. The preset duration can be appropriately extended. For example, for the gas-liquid separator of an industrial air conditioner with a large capacity, the first preset duration can be 2 minutes, the second preset duration is 8 minutes, and the third preset duration is 14 minutes. For a gas-liquid separator with a normal capacity, the first preset duration can be 1 minute, the second preset duration is 5 minutes, and the third preset duration is 10 minutes. Or the ambient temperature and humidity of the air conditioner's usage environment can be considered. In a high-temperature and high-humidity environment, the evaporation and condensation processes of the refrigerant will be affected, and the liquid level fluctuates greatly. The preset duration also needs to be adjusted accordingly. For example, for an air conditioner used in a high-temperature and high-humidity environment in the tropical region, the first preset duration may be 45 seconds, the second preset duration is 4 minutes, and the third preset duration is 8 minutes.

[0056] In short, by comparing the temperatures detected by multiple temperature sensors distributed at intervals in the height direction with the evaporation temperature, the liquid level height in the gas-liquid separator can be accurately monitored based on the comparison results. Thus, the heating duration of the heating device can be accurately controlled to ensure that the liquid level in the gas-liquid separator is reduced below the target liquid level, avoiding the occurrence of compressor liquid slug phenomenon. In addition, it can also prevent the internal pressure of the heating device from rising sharply due to overheating, and avoid damage to the gas-liquid separator caused by excessive pressure.

[0057] As a possible implementation manner, the control method of the present invention further includes: when the third temperature > evaporation temperature > the second temperature and the first temperature, controlling the heating device to heat for a second preset duration. Generally, only when the evaporation temperature is greater than the second temperature, it can be determined that the liquid level height has reached the position where the second temperature sensor is located. During actual operation, the temperature sensor may fail due to long-term use, environmental interference, or its own quality problems. Once a certain temperature sensor fails and outputs an incorrect signal, if the liquid level position is determined only based on the comparison between the single evaporation temperature and the second temperature, it may lead to misjudgment. The present invention further determines that the liquid level of the gas-liquid separator has reached the position where the second temperature sensor is located and controls the heating device to heat for the second preset duration only when the evaporation temperature is greater than both the first temperature and the second temperature. By adopting a dual guarantee mechanism, it can effectively avoid the incorrect judgment caused by the failure of the temperature sensor, and greatly improve the accuracy and reliability of the air conditioner in liquid level monitoring and control.

[0058] Similarly, when the evaporation temperature > the first temperature, the second temperature, and the third temperature, the heating device is controlled to heat for a third preset duration. It can further avoid the incorrect judgment caused by the failure of the temperature sensor, and greatly improve the accuracy and reliability of the air conditioner in liquid level monitoring and control.

[0059] As an alternative implementation manner, controlling the heating device to heat for a first preset duration can be replaced by controlling the heating device to heat at a first preset power. Controlling the heating device to heat for a second preset duration can be replaced by controlling the heating device to heat at a second preset power. Controlling the heating device to heat for a third preset duration can be replaced by controlling the heating device to heat at a third preset power. Among them, the third preset power > the second preset power > the first preset power.

[0060] When the liquid level is at different heights, for example, at a relatively low liquid level one, controlling the heating device to heat at a relatively low power can ensure that the liquid level drops below the target liquid level. When the liquid level rises to a liquid level two higher than the liquid level one, appropriately increasing the power can accelerate the liquid level drop speed and meet the timeliness requirement of liquid level control. When the liquid level rises to a liquid level three higher than the liquid level two, controlling the heating device to heat at a greater power can quickly evaporate a large amount of liquid and efficiently lower the liquid level below the target liquid level. In short, the above method can enable the heating device to output the most suitable power to achieve rapid and accurate adjustment of the liquid level, and effectively prevent serious faults such as liquid slugging of the compressor.

[0061] The values of the above-mentioned first preset power, second preset power, and third preset power are not fixed, but need to comprehensively consider various factors and be flexibly adjusted. For example, for a 3-horsepower household central air conditioner with relatively large cooling capacity and a gas-liquid separator volume of about 3 liters, in a normal use environment in temperate regions. Considering its strong cooling capacity and moderate gas-liquid separator volume, the first preset power can be set to 400 watts, the second preset power can be set to 800 watts, and the third preset power can be determined to be 1200 watts. Another example is a 1-horsepower small wall-mounted air conditioner with a gas-liquid separator volume of about 1.5 liters. In a tropical region with poor room ventilation, the first preset power may be 250 watts, the second preset power is 500 watts, and the third preset power is 750 watts. For another example, for an 8-horsepower large commercial air conditioner with a gas-liquid separator volume of 8 liters, when used in a relatively dry and cold region, the first preset power may be 600 watts, the second preset power is 1200 watts, and the third preset power is 1800 watts.

[0062] As a possible implementation manner, the control method of the present invention further includes: when operating in the heating mode, before reaching the frosting condition, controlling the heating device to heat. Thereby heating the liquid refrigerant in the gas-liquid separator, increasing the circulation amount of the refrigerant in the air conditioner, thereby improving the heating capacity, and at the same time reducing the frosting amount.

[0063] As a possible implementation manner, the step of "before reaching the frosting condition, controlling the heating device to heat" further includes: obtaining the pipe temperature of the outdoor heat exchanger, and when the pipe temperature is less than or equal to the preset temperature, controlling the heating device to heat. Among them, a temperature sensor can be set on the outdoor heat exchanger to detect the pipe temperature of the outdoor heat exchanger. When the pipe temperature is less than or equal to the preset temperature, it means that the outdoor heat exchanger has frosted or is about to frost. At this time, controlling the heating device to heat to increase the circulation amount of the refrigerant in the air conditioner, thereby improving the heating capacity, and at the same time reducing the frosting amount.

[0064] Among them, the present invention does not limit the specific value of the preset temperature. The preset temperature can be determined through experiments or adjusted according to the temperature range recommended in the equipment manual. For example, -3°C to 0°C, specifically -2°C, 0°C, etc.

[0065] As a possible implementation manner, the step of "controlling the heating device to heat before the frosting condition is reached" further includes: when the time interval from the last defrosting operation time / the end of the last defrosting to the current time is greater than or equal to a preset percentage, controlling the heating device to heat. When the time interval from the last defrosting operation time / the end of the last defrosting to the current time is greater than or equal to a preset percentage, it means that the time interval after the last defrosting is short, while the defrosting time is long, indicating that the frost layer accumulates quickly. In this case, the surface of the outdoor heat exchanger is prone to quickly frosting, resulting in a decrease in heat exchange efficiency. By starting the heating device at this time, the frosting can be prevented from getting worse, ensuring that the system can continuously maintain a good heating efficiency.

[0066] The present invention does not specifically limit the value of the preset percentage. For example, when the external environmental temperature is low and the humidity is high, the frost layer generates quickly. At this time, the preset percentage can be set to more than 95%, such as 95%, to ensure that the sufficient time interval after each defrosting can remove the frost layer and avoid its serious impact on the heating effect. In an environment with a high temperature and low humidity, the frost layer generates slowly, and the preset percentage can be set to about 70%-80%, such as 72%, 75%, to reduce the defrosting frequency, thereby improving the energy efficiency and operation stability of the system.

[0067] Although the above steps are described in the above sequential manner in the above embodiments, those skilled in the art can understand that in order to achieve the effects of this embodiment, different steps do not have to be executed in such an order, and they can be executed simultaneously (in parallel) or in a reversed order. For example, step S100 and step S200 can be executed in reverse or in parallel, and these simple changes are all within the protection scope of the present invention.

[0068] Those skilled in the art can understand that the above air conditioner includes some other well-known structures, such as a processor, a controller, a memory, etc. Among them, the memory includes but is not limited to a random access memory, a flash memory, a read-only memory, a programmable read-only memory, a volatile memory, a non-volatile memory, a serial memory, a parallel memory, or a register, etc. The processor includes but is not limited to a CPLD / FPGA, a DSP, an ARM processor, a MIPS processor, etc. In order not to unnecessarily obscure the embodiments of the present disclosure, these well-known structures are not shown in the drawings. The memory is adapted to store multiple program codes, and the program codes are adapted to be loaded and run by the processor to execute the control method of the air conditioner.

[0069] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A gas-liquid separator for an air conditioner, characterized in that, Comprising: A cavity; A heating device for heating the liquid in the cavity; At least one temperature sensor disposed in the cavity and above the target liquid level of the cavity, so that when the temperature detected by at least one of the temperature sensors is less than the evaporation temperature, the liquid level in the cavity is below the target liquid level by heating with the heating device.

2. The gas-liquid separator of an air conditioner according to claim 1, wherein The temperature sensor includes a first temperature sensor, a second temperature sensor, and a third temperature sensor that are sequentially spaced apart from bottom to top; and / or The heating device is configured as a heating rod, the heating rod is disposed in the cavity and arranged along the height direction of the cavity; a tube body is sleeved outside the heating rod, and the temperature sensor is disposed on the side wall of the tube body.

3. An air conditioner, characterized in that, The air conditioner includes the gas-liquid separator according to claim 1 or 2.

4. A control method for an air conditioner, characterized in that, The air conditioner includes a gas-liquid separator, and the gas-liquid separator includes: A cavity; A heating device for heating the liquid in the cavity; At least one temperature sensor disposed in the cavity and above the target liquid level of the cavity; The control method includes: When the air conditioner is operating, obtaining the evaporation temperature; Obtaining the temperature detected by the temperature sensor; Comparing the magnitudes of the evaporation temperature and the temperature detected by the temperature sensor; When the temperature detected by at least one of the temperature sensors is less than the evaporation temperature, controlling the heating device to heat so that the liquid level in the cavity is below the target liquid level.

5. The control method of an air conditioner according to claim 4, wherein The temperature sensor includes a first temperature sensor, a second temperature sensor, and a third temperature sensor that are sequentially spaced apart from bottom to top. The first temperature sensor is used to detect a first temperature, the second temperature sensor is used to detect a second temperature, and the third temperature sensor is used to detect a third temperature; The step of "when the temperature detected by at least one of the temperature sensors is less than the evaporation temperature, controlling the heating device to heat" further includes: When the second temperature > the evaporation temperature > the first temperature, controlling the heating device to heat for a first preset duration or at a first preset power; When the third temperature > the evaporation temperature > the second temperature, controlling the heating device to heat for a second preset duration or at a second preset power; Wherein, the second preset duration is greater than the first preset duration, and the second preset power is greater than the first preset power.

6. The control method of an air conditioner according to claim 5, wherein The step of "when the temperature detected by at least one of the temperature sensors is less than the evaporation temperature, controlling the heating device to heat" further includes: When the evaporation temperature > the third temperature, controlling the heating device to heat for a third preset duration or at a third preset power; Wherein, the third preset duration is greater than the second preset duration, and the third preset power is greater than the second preset power.

7. The control method of an air conditioner according to claim 5, wherein The step of "when the third temperature > the evaporation temperature > the second temperature, controlling the heating device to heat for a second preset duration or at a second preset power" further includes: When the third temperature > the evaporation temperature > the second temperature and the first temperature, controlling the heating device to heat for a second preset duration or at a second preset power.

8. The control method of an air conditioner according to claim 6, wherein: The step of "when the evaporation temperature > the third temperature, controlling the heating device to heat for a third preset duration or at a third preset power" further includes: When the evaporation temperature > the first temperature, the second temperature, and the third temperature, controlling the heating device to heat for a third preset duration or at a third preset power.

9. The control method of an air conditioner according to claim 4, wherein: The control method further includes: During the heating mode operation, before reaching the frosting condition, controlling the heating device to heat.

10. The control method of an air conditioner according to claim 9, wherein: The step of "before reaching the frosting condition, controlling the heating device to heat" further includes: Obtaining the pipe temperature of the outdoor heat exchanger; When the pipe temperature is less than or equal to a preset temperature, controlling the heating device to heat; and / or When the time interval from the last defrosting operation time / the time from the end of the last defrosting to the current time is greater than or equal to a preset percentage, controlling the heating device to heat.

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