Control method of air conditioner

Abstract

The present invention relates to the technical field of air conditioners, and specifically provides a control method for an air conditioner, aiming to solve the problem in the prior art that due to the limited degree of subcooling that can be provided by the air-cooled condenser of the air conditioner, the temperature of the indoor space cannot be adjusted well. For this purpose, the air conditioner of the present invention is configured with a rechiller, at least a part of the refrigerant pipeline located between the condenser and the throttling device is arranged in the rechiller, and a drain valve is arranged on the rechiller. The control method of the present invention includes: obtaining the operating mode of the air conditioner, and controlling the drain valve to open or close according to the operating mode. By controlling the drain valve to open or close according to the air conditioner operating mode, it is possible to determine whether to further reduce the temperature of the refrigerant by the condensed water in the rechiller as needed, so that the temperature of the refrigerant can be better adjusted, and then the temperature and humidity of the indoor space can be better adjusted.

Description

Technical Field

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

[0002] Currently, during the refrigeration process of an air conditioner, the air in the indoor space enters the indoor unit of the air conditioner and exchanges heat with the evaporator. The refrigerant absorbs heat at the evaporator, thereby being able to reduce the temperature of the air exchanging heat with it. After the refrigerant absorbs heat at the evaporator, it flows along the refrigerant pipeline to the air-cooled condenser of the outdoor unit, and exchanges heat with the outdoor air and dissipates heat at the air-cooled condenser, thereby reducing the temperature of the refrigerant. The refrigerant with a reduced temperature then returns to the evaporator to exchange heat with the air in the indoor space, and so on, thereby achieving the purpose of reducing the temperature of the indoor space.

[0003] However, the cooling capacity that the air-cooled condenser can provide is limited, which results in the subcooling degree of the refrigerant not being low enough, and further leads to the limited cooling capacity that the refrigerant can provide. Currently, usually, a subcooling pipe section is added to increase the subcooling degree of the refrigerant. However, since the heat exchange efficiency of the air-cooled condenser is greatly affected by the ambient temperature, the subcooling degree that the added subcooling pipe section can provide is also limited, and it cannot well meet the demand for cooling capacity, resulting in the air conditioner being unable to well adjust the temperature of the indoor space.

[0004] Correspondingly, the present field needs a new technical solution to solve the above problems. Summary of the Invention

[0005] The present invention aims to solve the above technical problems, that is, to solve the problem in the prior art that due to the limited subcooling degree that the air-cooled condenser of the air conditioner can provide, the temperature of the indoor space cannot be well adjusted.

[0006] The present invention provides a control method for an air conditioner. The air conditioner includes a compressor, a condenser, a throttling device, and an evaporator. The refrigerant circulates among the compressor, the condenser, the throttling device, and the evaporator. The air conditioner further includes a subcooler, the subcooler is arranged between the condenser and the throttling device, condensed water is stored in the subcooler, the subcooler is configured to be able to adjust the temperature of the refrigerant between the condenser and the throttling device, a drain valve is arranged on the subcooler, and the drain valve is configured to allow the condensed water in the subcooler to be discharged when it is opened. The control method includes: obtaining the operating mode of the air conditioner; controlling the drain valve to be opened or closed according to the operating mode.

[0007] In a preferred technical solution of the above control method, if the operating mode is the refrigeration mode, the control method further includes: obtaining the outdoor temperature; comparing the outdoor temperature with a first preset temperature; if the outdoor temperature is less than the first preset temperature, controlling the drain valve to open; if the outdoor temperature is greater than or equal to the first preset temperature, controlling the drain valve to close.

[0008] In a preferred technical solution of the above control method, the throttling device is an electronic expansion valve, and the control method further includes: after controlling the drain valve to close, obtaining the first refrigerant temperature at the outlet of the electronic expansion valve; comparing the first refrigerant temperature with a second preset temperature; if the first refrigerant temperature is greater than or equal to the second preset temperature, controlling the opening degree of the electronic expansion valve to remain unchanged; if the first refrigerant temperature is less than the second preset temperature, increasing the opening degree of the electronic expansion valve.

[0009] In a preferred technical solution of the above control method, the control method further includes: after increasing the opening degree of the electronic expansion valve to the maximum opening degree, obtaining the second refrigerant temperature at the outlet of the electronic expansion valve; after obtaining the second refrigerant temperature for a first preset duration, obtaining the third refrigerant temperature at the outlet of the electronic expansion valve again; judging whether the refrigerant temperature at the outlet of the electronic expansion valve is in a downward trend according to the second refrigerant temperature and the third refrigerant temperature; selectively controlling the drain valve to remain in the closed state according to the judgment result.

[0010] In a preferred technical solution of the above control method, the step of "selectively controlling the drain valve to remain in the closed state according to the judgment result" specifically includes: if the refrigerant temperature at the outlet of the electronic expansion valve is in a downward trend, further obtaining the fourth refrigerant temperature at the outlet of the electronic expansion valve, and selectively controlling the drain valve to remain in the closed state according to the magnitude of the fourth refrigerant temperature; if the refrigerant temperature at the outlet of the electronic expansion valve is in an upward trend, controlling the drain valve to remain in the closed state.

[0011] In a preferred technical solution of the above control method, the step of "selectively controlling the drain valve to remain in the closed state according to the magnitude of the fourth refrigerant temperature" specifically includes: comparing the fourth refrigerant temperature with a third preset temperature; if the fourth refrigerant temperature is less than the third preset temperature, controlling the drain valve to open; if the fourth refrigerant temperature is greater than or equal to the third preset temperature, controlling the drain valve to remain in the closed state.

[0012] In a preferred technical solution of the above control method, the control method further includes: after controlling the water discharge valve to open for a second preset duration, acquiring the fifth refrigerant temperature at the outlet of the electronic expansion valve again; comparing the magnitude of the fifth refrigerant temperature with a fourth preset temperature; if the fifth refrigerant temperature is greater than or equal to the fourth preset temperature, controlling the water discharge valve to close.

[0013] In a preferred technical solution of the above control method, if the operating mode is a dehumidification mode, the control method further includes: controlling the water discharge valve to close.

[0014] In a preferred technical solution of the above control method, the control method further includes: after controlling the water discharge valve to close for a third preset duration, acquiring the sixth refrigerant temperature at the outlet of the throttling device; comparing the magnitude of the sixth refrigerant temperature with a fifth preset temperature; if the sixth refrigerant temperature is less than the fifth preset temperature, controlling the water discharge valve to open; if the sixth refrigerant temperature is greater than or equal to the fifth preset temperature, controlling the water discharge valve to continue to maintain a closed state.

[0015] In a preferred technical solution of the above control method, the control method further includes: after controlling the water discharge valve to open for a fourth preset duration, acquiring the seventh refrigerant temperature at the outlet of the throttling device again; comparing the magnitude of the seventh refrigerant temperature with a sixth preset temperature; if the seventh refrigerant temperature is less than the sixth preset temperature, controlling the water discharge valve to continue to maintain an open state; if the seventh refrigerant temperature is greater than or equal to the sixth preset temperature, controlling the water discharge valve to close.

[0016] In the technical solution of the present invention, the air conditioner includes a compressor, a condenser, a throttling device, and an evaporator. The refrigerant circulates among the compressor, the condenser, the throttling device, and the evaporator. By the heat release or absorption of the refrigerant at the evaporator and the heat exchange between the indoor air and the evaporator, the temperature and humidity of the indoor space are adjusted. The air conditioner further includes a subcooler, which is arranged between the condenser and the throttling device. Condensate can be stored in the subcooler. At least a part of the refrigerant pipeline located between the condenser and the throttling device is arranged in the subcooler. In this way, the condensate water provided in the subcooler can be used to reduce the temperature of the refrigerant flowing through this section of the refrigerant pipeline, and further reduce the temperature of all the refrigerant. A drain valve is arranged on the subcooler. When the drain valve is opened, the condensate water in the subcooler can be discharged from the subcooler. When the subcooler is required to provide subcooling, the drain valve is closed to accumulate condensate water in the subcooler. In this way, the refrigerant flowing through the refrigerant pipeline located in the subcooler can further reduce its temperature by exchanging heat with the condensate water in the subcooler. When the subcooler is not required to provide subcooling, the drain valve is opened to discharge the condensate water in the subcooler. The refrigerant only flows through the refrigerant pipeline located in the subcooler and will not be further cooled. Through such a setting method, the temperature of the refrigerant can be adjusted as needed, providing a more suitable refrigerating capacity and better adjusting the temperature and humidity of the indoor space.

[0017] The control method of the present invention includes: obtaining the operation mode of the air conditioner and controlling the opening or closing of the drain valve according to the operation mode. Through such a control method, controlling the opening or closing of the drain valve according to the operation mode of the air conditioner, that is, controlling whether condensate water is stored in the subcooler according to the operation mode of the air conditioner. In this way, it can be determined whether to further reduce the temperature of the refrigerant by condensate water as needed, so that the temperature of the refrigerant can be better adjusted, and further the temperature and humidity of the indoor space can be better adjusted.

[0018] If the operating mode of the air conditioner is the cooling mode, the control method of the present invention further includes: obtaining the outdoor temperature, comparing the outdoor temperature with the first preset temperature. If the outdoor temperature is lower than the first preset temperature, it indicates that the outdoor temperature is relatively low, and the condenser can meet the demand for cooling capacity, and there is no need to provide additional subcooling through the condensate. At this time, the drain valve is controlled to open to discharge the condensate to prevent the air outlet temperature of the air conditioner from being too low or the evaporator from frosting due to the too low temperature of the refrigerant. If the outdoor temperature is greater than or equal to the first preset temperature, it indicates that the outdoor temperature is relatively high, and the condenser cannot meet the demand for cooling capacity. At this time, the drain valve is controlled to close, so that the condensate accumulates in the subcooler, and the temperature of the refrigerant is further reduced through the condensate in the subcooler to increase the subcooling degree of the refrigerant and provide more cooling capacity for the indoor space, thereby being able to better reduce the temperature of the indoor space. Through such a control method, the opening and closing of the drain valve are controlled according to the size of the outdoor temperature, so as to better meet the current demand for cooling capacity and better reduce the temperature of the indoor space.

[0019] Further, the throttling device is an electronic expansion valve, and the flow rate of the refrigerant in the refrigerant pipeline can be adjusted by adjusting the opening degree of the electronic expansion valve. The control method of the present invention further includes: after controlling the drain valve to close, obtaining the first refrigerant temperature at the outlet of the electronic expansion valve, comparing the first refrigerant temperature with the second preset temperature. If the first refrigerant temperature is greater than or equal to the second preset temperature, it indicates that the temperature of the refrigerant is relatively appropriate at this time, the air outlet temperature of the air conditioner will not be too low, and the evaporator will not frost. At this time, the opening degree of the electronic expansion valve is controlled to remain unchanged. If the first refrigerant temperature is lower than the second preset temperature, it indicates that the temperature of the refrigerant is relatively low at this time, the subcooling degree of the refrigerant is relatively high, which will cause the air outlet temperature of the air conditioner to be relatively low or the evaporator to frost. At this time, the opening degree of the electronic expansion valve is increased to increase the flow rate of the refrigerant, so that the amount of cold that can be obtained by the refrigerant per unit volume per unit time can be reduced, and the purpose of appropriately increasing the temperature of the refrigerant can be achieved.

[0020] Further, the control method further includes: after increasing the opening degree of the electronic expansion valve to the maximum opening degree, obtaining the second refrigerant temperature at the outlet of the electronic expansion valve; after obtaining the second refrigerant temperature for a first preset duration, obtaining the third refrigerant temperature at the outlet of the electronic expansion valve again; and judging whether the refrigerant temperature at the outlet of the electronic expansion valve is in a downward trend according to the magnitudes of the second refrigerant temperature and the third refrigerant temperature. If the third refrigerant temperature is less than the second refrigerant temperature, it indicates that the refrigerant temperature at the outlet of the electronic expansion valve is in a downward trend. At this time, the fourth refrigerant temperature at the outlet of the electronic expansion valve is further obtained, and the magnitudes of the fourth refrigerant temperature and a third preset temperature are compared. If the fourth refrigerant temperature is less than the third preset temperature, it indicates that the current temperature of the refrigerant is still relatively low, and there are problems such as too low air outlet temperature or frosting of the evaporator. At this time, the drain valve is controlled to open to discharge the condensed water in the subcooler, and no additional subcooling is provided by the condensed water, so as to increase the temperature of the refrigerant. If the fourth refrigerant temperature is greater than or equal to the third preset temperature, it indicates that although the current temperature of the refrigerant is in a downward trend, the temperature of the refrigerant is not too low, the air outlet temperature will not be too low, and the evaporator basically will not have frosting problems. At this time, the drain valve is controlled to remain in the closed state. If the third refrigerant temperature is greater than the second refrigerant temperature, it indicates that the refrigerant temperature at the outlet of the electronic expansion valve is in an upward trend, which means that after opening the opening degree of the electronic expansion valve to the maximum opening degree, the temperature of the refrigerant can be effectively increased, and no other means are needed to increase the temperature of the refrigerant. At this time, the drain valve is controlled to remain in the closed state. Through such a control method, the temperature of the refrigerant can be controlled within a more appropriate range, so as to better adjust the temperature of the indoor space.

[0021] Further, the control method further includes: after controlling the drain valve to open for a second preset duration, obtaining the fifth refrigerant temperature at the outlet of the electronic expansion valve again, and comparing the magnitudes of the fifth refrigerant temperature and a fourth preset temperature. If the fifth refrigerant temperature is greater than or equal to the fourth preset temperature, it indicates that the temperature of the refrigerant has risen to a more appropriate temperature. If it continues to operate in the current state, the temperature of the refrigerant will continue to rise, and the refrigerating capacity provided by the refrigerant will decrease. At this time, the drain valve is controlled to close to accumulate the condensed water in the subcooler and further reduce the temperature of the refrigerant. Through such a control method, the temperature of the refrigerant can be controlled within a more appropriate range, avoiding the situation that the air outlet temperature is too high due to too high refrigerant temperature and thus unable to meet the refrigeration demand, or too low air outlet temperature and even frosting of the evaporator due to too low refrigerant temperature.

[0022] If the operating mode of the air conditioner is the dehumidification mode, the control method of the present invention further includes: controlling the drain valve to close. When the air conditioner operates in the dehumidification mode, regardless of the indoor and outdoor ambient temperatures, the subcooling is first provided by the condensed water to reduce the temperature of the refrigerant and quickly remove the moisture in the indoor air to improve the user experience.

[0023] Further, the control method of the present invention further includes: after controlling the drain valve to close for a third preset duration, obtaining the sixth refrigerant temperature at the outlet of the throttling device, comparing the sixth refrigerant temperature with a fifth preset temperature. If the sixth refrigerant temperature is less than the fifth preset temperature, it indicates that the refrigerant temperature is on the low side. At this time, control the drain valve to open to drain the condensate water to prevent the outlet air temperature from being too low or the evaporator from frosting. If the sixth refrigerant temperature is greater than or equal to the fifth preset temperature, it indicates that the refrigerant temperature is relatively appropriate. At this time, control the drain valve to continue to maintain the closed state and continue to reduce the temperature of the refrigerant through the condensate water to ensure the dehumidification effect. Through such a control method, after the drain valve is closed for the third preset duration, the opening or closing of the drain valve is controlled according to the temperature of the refrigerant at the outlet of the throttling device, so as to be able to ensure the dehumidification effect while avoiding the occurrence of situations such as too low outlet air temperature or evaporator frosting, and improving the user experience.

[0024] Further, the control method of the present invention further includes: after controlling the drain valve to open for a fourth preset duration, since there is no condensate water to further reduce the temperature of the refrigerant, the refrigerant temperature at the outlet of the throttling device will gradually increase. At this time, obtain the seventh refrigerant temperature at the outlet of the throttling device again, compare the seventh refrigerant temperature with a sixth preset temperature. If the seventh refrigerant temperature is less than the sixth preset temperature, it indicates that the refrigerant temperature at the outlet of the throttling device is still on the low side. At this time, control the drain valve to continue to maintain the open state in order to increase the temperature of the refrigerant. If the seventh refrigerant temperature is greater than or equal to the sixth preset temperature, it indicates that the refrigerant temperature at the outlet of the throttling device is a bit high. If its temperature is not reduced, it may continue to rise, which may lead to too high a temperature at the evaporator and ineffective dehumidification. At this time, control the drain valve to close and further reduce the temperature of the refrigerant through the condensate water, thereby reducing the temperature at the evaporator and improving the dehumidification efficiency. Through such a control method, after controlling the drain valve to open for the fourth preset duration, the opening or closing of the drain valve is controlled according to the temperature at the outlet of the throttling device, so as to be able to control the refrigerant temperature within an appropriate range and improve the dehumidification efficiency. Description of the Drawings

[0025] The following takes a wall-mounted air conditioner as an example and describes the preferred embodiments of the present invention in conjunction with the drawings. In the drawings:

[0026] Figure 1 is a schematic structural diagram of a wall-mounted air conditioner according to an embodiment of the present invention;

[0027] Figure 2 is a schematic structural diagram of a sub-cooler and a condenser of a wall-mounted air conditioner according to an embodiment of the present invention;

[0028] Figure 3 is a schematic structural diagram of a sub-cooler of a wall-mounted air conditioner according to an embodiment of the present invention;

[0029] Figure 4 is a flowchart of the control method of a wall-mounted air conditioner according to an embodiment of the present invention;

[0030] Figure 5 is the control flowchart (1) when the operation mode of a wall-mounted air conditioner according to an embodiment of the present invention is cooling;

[0031] Figure 6 is the control flowchart (2) when the operation mode of a wall-mounted air conditioner according to an embodiment of the present invention is cooling;

[0032] Figure 7 is the control flowchart (3) when the operation mode of a wall-mounted air conditioner according to an embodiment of the present invention is cooling;

[0033] Figure 8 is the control flowchart (4) when the operation mode of a wall-mounted air conditioner according to an embodiment of the present invention is cooling;

[0034] Figure 9 is the control flowchart (1) when the operation mode of a wall-mounted air conditioner according to an embodiment of the present invention is the dehumidification mode;

[0035] Figure 10 is the control flowchart (2) when the operation mode of a wall-mounted air conditioner according to an embodiment of the present invention is the dehumidification mode.

[0036] List of reference numerals:

[0037] 1. Condenser; 2. Throttling device; 3. Evaporator; 4. Re-cooler; 41. Overflow port; 411. Overflow pipe; 42. Water inlet; 421. Water inlet pipe; 43. Drain valve; 44. Drain port; 441. Drain pipe; 5. Compressor; 6. First filter screen; 7. Third filter screen. Specific embodiments

[0038] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention. Although this embodiment is described by taking a wall-mounted air conditioner as an example, it can also be applied to other types of air conditioners such as ceiling-mounted air conditioners and cabinet air conditioners.

[0039] It should be noted that in the description of the present invention, the terms "first", "second", "third", "fourth", "fifth", "sixth", and "seventh" are only used for descriptive purposes and should not be construed as indicating or implying relative importance. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances. In addition, it should also be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "connected" and "joined" 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 a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] Currently, it is usually to increase the length of the subcooling pipe section of the air-cooled condenser to increase the subcooling degree of the refrigerant. However, since the air-cooled condenser is greatly affected by the ambient temperature, the increased subcooling pipe section can provide limited subcooling degree for the condenser and cannot well meet the demand for refrigeration capacity. For this reason, the present invention controls the opening or closing of the drain valve according to the air-conditioning operation mode, and determines whether to further reduce the temperature of the refrigerant through the condensate according to the need, so as to better adjust the temperature of the refrigerant, and then better adjust the temperature and humidity of the indoor space.

[0041] First, refer to Figures 1 to 3 to describe the possible implementation manners of the wall-mounted air conditioner of the present invention.

[0042] As Figure 1 shown, the wall-mounted air conditioner includes a compressor, a condenser 1, a throttling device 2, and an evaporator 3. The compressor 5, the condenser 1, the throttling device 2, and the evaporator 3 are sequentially connected through a refrigerant pipeline and form a closed loop. The refrigerant circulates between the compressor 5, the condenser 1, the throttling device 2, and the evaporator 3 along the refrigerant pipeline. By the refrigerant releasing or absorbing heat at the evaporator 3 and the heat exchange between the air in the indoor space and the evaporator, the purpose of adjusting the temperature and humidity of the indoor space is achieved. The wall-mounted air conditioner further includes a subcooler 4, and the subcooler 4 is arranged between the condenser 1 and the throttling device 2. The subcooler 4 can store condensate. At least a part of the refrigerant pipeline located between the condenser 1 and the throttling device 2 is arranged in the subcooler 4. In this way, the condensate provided in the subcooler 4 can be used to reduce the temperature of the refrigerant flowing through this section of the refrigerant pipeline, and then reduce the temperature of all the refrigerant.

[0043] As Figure 2 and Figure 3 shown and in accordance with Figure 2In the orientation shown, the cross-section of the reheater 4 is generally a rectangular structure. The refrigerant pipeline connected to the condenser 1 penetrates into the reheater 4 from the left side of the reheater 4 and then exits from the right side, and is connected to the throttling device 2 after exiting. The refrigerant pipeline located in the reheater 4 can be set in possible shapes such as a straight line, an S shape, a wavy shape, etc. An overflow port 41 is provided on the left side of the reheater 4, and this overflow port is close to the top of the reheater 4. An overflow pipe 411 is provided at the overflow port 41. When the condensed water in the reheater 4 reaches or exceeds the overflow port 41, it can flow out from the overflow port 41 and be drained to a specified position through the overflow pipe 411, avoiding the poor user experience caused by the water level in the reheater 4 being too high and overflowing from the top of the reheater 4 to the ground. A first filter screen 6 is provided at the end of the overflow pipe 411 away from the overflow port 41. Through this first filter screen 6, it is possible to prevent foreign objects from entering the reheater 4 through the overflow pipe 411.

[0044] As Figures 2 to 3 shown, an inlet 42 is also provided on the reheater 4. External water can enter the reheater 4 through this inlet 42. A water receiving tray is provided below the evaporator, and this water receiving tray is used to receive the condensed water condensed on the surface of the evaporator. An inlet pipe 421 is provided at the inlet 42. Through this inlet pipe 421, the reheater 4 can be connected to the water receiving tray, so that the condensed water accumulated in the water receiving tray can be introduced into the reheater 4. In this way, the temperature of the refrigerant can be further reduced by using the condensed water, and at the same time, the cold quantity of this part of the condensed water can be recovered, avoiding waste of resources. The end of the inlet pipe 421 close to the reheater 4 extends into the reheater 4, and a second filter screen (not shown) is provided at the end of it located in the reheater 4. Through this second filter screen, it is possible to prevent foreign objects from entering the reheater together with the condensed water. Obviously, the inlet pipe 421 can also not extend into the reheater 4. In this case, the second filter screen can be provided at the inlet 42.

[0045] Obviously, the inlet 42 of the reheater 4 can also not be connected to the water receiving tray, but be connected to an external water source (such as tap water, etc.), and condensed water is added to the reheater 4 through this external water source.

[0046] As Figures 2 to 3 shown and in accordance with Figure 2In the orientation shown, a drain port 44 is provided on the right side of the aftercooler 4, and this drain port 44 is close to the bottom of the aftercooler. A drain pipe 441 is provided at the drain port 44, and a drain valve 43 is provided on the drain pipe 441. When the drain valve 43 is opened, the condensed water in the aftercooler 4 can be discharged through the drain port 44 and the drain pipe 441. When the drain valve 43 is closed, condensed water can accumulate in the aftercooler 4, and in this way, the temperature of the refrigerant flowing through the refrigerant pipeline located in the aftercooler 4 can be further reduced by the condensed water in the aftercooler 4. A third filter screen 7 is provided at the end of the drain pipe 441 away from the drain port 44, and through this third filter screen 7, foreign matters from the outside can be prevented from entering the aftercooler through the drain pipe 441.

[0047] In the present invention, the wall-mounted air conditioner is equipped with a first temperature sensor, and the outdoor temperature can be detected through this first temperature sensor.

[0048] It should be noted that the first temperature sensor can be, but is not limited to, a thermocouple or a thermal resistor.

[0049] It should be noted that the wall-mounted air conditioner may not be equipped with a first temperature sensor. Instead, the wall-mounted air conditioner may be equipped with a positioning module and a communication module. The wall-mounted air conditioner can accurately determine its location through the positioning module, and the wall-mounted air conditioner can communicate with the Internet through the communication module in at least one of the following ways: Bluetooth, WiFi, Mesh, ZigBee, Thread, Z-Wave, NFC, Hilink, UWB, LiFi. When it is necessary to obtain the outdoor temperature, the current outdoor temperature at the location of the wall-mounted air conditioner can be directly queried through the Internet platform. It should be noted that the positioning module can be one or a combination of multiple devices such as a Bluetooth positioning system, a global satellite positioning system (GPS), a radio tower positioning system, a Beidou positioning system, a global satellite navigation system (GNSS), a WiFi positioning system, etc. that can determine the location of the washing equipment.

[0050] In a possible implementation manner, the throttling device is an electronic expansion valve, and the flow rate of the refrigerant in the wall-mounted air conditioner can be adjusted by adjusting the opening degree of the electronic expansion valve. Obviously, the throttling device can also be other throttling elements such as a capillary tube.

[0051] In the present invention, a second temperature sensor is provided at the outlet of the throttling device, and the refrigerant temperature at the outlet of the throttling device can be detected through this second temperature sensor.

[0052] It should be noted that the second temperature sensor can be, but is not limited to, a thermocouple or a thermal resistor.

[0053] In the present invention, the drum washing machine further includes a control module, which is respectively connected to a drain valve, a first temperature sensor, a second temperature sensor, and an electronic expansion valve. The control module can control the opening or closing of the drain valve according to the operating mode of the wall-mounted air conditioner. When the operating mode of the wall-mounted air conditioner is the cooling mode, it can control the opening or closing of the drain valve according to the magnitude of the outdoor temperature or the magnitude of the refrigerant temperature at the outlet of the electronic expansion valve. It can also control the opening degree of the electronic expansion valve according to the magnitude of the first refrigerant temperature at the outlet of the electronic expansion valve. When the operating mode of the wall-mounted air conditioner is the dehumidification mode, it can control the opening or closing of the drain valve according to the magnitude of the refrigerant temperature at the outlet of the electronic expansion valve.

[0054] It should be noted that physically, this control module can be a control chip inherent in the wall-mounted unit itself, or a controller specifically used to execute the method of the present application, or also a functional module or functional unit of a general controller.

[0055] Next, with reference to Figures 4 to 10 the possible implementation manners of the control method of the wall-mounted air conditioner of the present invention will be described.

[0056] As Figure 4 shown, in a possible implementation manner, the control method of the present invention includes:

[0057] S100: Obtain the operating mode of the wall-mounted air conditioner;

[0058] S101: Control the drain valve to open or close according to the operating mode.

[0059] In S100, the operating mode of the wall-mounted air conditioner is obtained.

[0060] In S101, based on the operating mode obtained in S100, the drain valve is controlled to open or close. For example, when the operating mode is the dehumidification mode, the drain valve is controlled to close, so that the moisture in the indoor air can be removed as soon as possible and the humidity of the indoor space can be reduced.

[0061] Through such a control method, the drain valve is controlled to open or close according to the operating mode of the air conditioner, so that whether condensate water is stored in the rechiller can be controlled according to the operating mode of the air conditioner, and thus whether the refrigerant temperature can be further reduced by the condensate water can be determined according to the need, so that the refrigerant temperature can be better adjusted, and then the temperature and humidity of the indoor space can be better adjusted.

[0062] The control method of the drain valve is different when the operating mode of the wall-mounted air conditioner is different. Next, first with reference to Figures 5 to 8 the possible implementation manners of the control method of the wall-mounted air conditioner of the present invention when the operating mode is the cooling mode will be described.

[0063] AsFigure 5 As shown, in a possible implementation, the control method of the present invention further includes:

[0064] S200: Obtain the outdoor temperature;

[0065] S201: Determine whether the outdoor temperature is greater than or equal to the first preset temperature. If so, execute S202; if not, execute S203;

[0066] S202: Control the drain valve to close;

[0067] S203: Control the drain valve to open.

[0068] In S200, the outdoor temperature is obtained through the above-mentioned first temperature sensor.

[0069] In S201, based on the outdoor temperature obtained in S200, determine whether the outdoor temperature is greater than or equal to the first preset temperature.

[0070] If the outdoor temperature is greater than or equal to the first preset temperature, for example, the outdoor temperature is 40°C and the first preset temperature is 33°C, it indicates that the outdoor temperature is relatively high and the required cooling capacity is large, and the condenser cannot meet the demand for cooling capacity. At this time, control the drain valve to close, that is, execute S202. After the drain valve is closed, the condensed water accumulates in the subcooler, and the condensed water in the subcooler can further reduce the temperature of the refrigerant, increase the subcooling degree of the refrigerant, and provide more cooling capacity for the indoor space, so as to better reduce the temperature of the indoor space.

[0071] If the outdoor temperature is less than the first preset temperature, for example, the outdoor temperature is 31°C and the first preset temperature is 33°C, it indicates that the outdoor temperature is not very high and the required cooling capacity is not much, and the condenser can meet the demand for cooling capacity. There is no need to provide additional subcooling through condensed water. At this time, control the drain valve to open, that is, execute S203. There is no need to accumulate condensed water in the subcooler to prevent the temperature of the refrigerant from being too low, resulting in too low air outlet temperature of the air conditioner or frosting of the evaporator.

[0072] Through the above control method, the opening and closing of the drain valve are controlled according to the magnitude of the outdoor temperature, and thus the opening and closing of the drain valve can be controlled according to the actual demand for cooling capacity, so as to better meet the demand for cooling capacity, ensure the stable operation of the air conditioner, and better reduce the temperature of the indoor space.

[0073] After controlling the drain valve to close in S202, the refrigerant temperature at the outlet of the electronic expansion valve will decrease. Although it can increase the subcooling degree of the refrigerant, if the refrigerant temperature is too low, it will cause the outlet air temperature of the wall-mounted air conditioner to be too low or the evaporator to frost, which will instead reduce the user experience. At this time, in order to control the refrigerant temperature within a more appropriate range, the refrigerant temperature can be adjusted by adjusting the opening degree of the electronic expansion valve. The following will further elaborate on a possible implementation manner of the control method when the operating mode of the wall-mounted air conditioner of the present invention is the cooling mode in combination with Figures 6 to 8 to further illustrate a possible implementation manner of the control method of the wall-mounted air conditioner of the present invention when the operating mode is the cooling mode.

[0074] As Figure 6 shown, in a possible implementation manner, the control method of the present invention further includes:

[0075] S300: After controlling the drain valve to close, obtain the first refrigerant temperature at the outlet of the electronic expansion valve;

[0076] S301: Determine whether the first refrigerant temperature is greater than or equal to the second preset temperature. If so, execute S302; if not, execute S303;

[0077] S302: Keep the opening degree of the electronic expansion valve unchanged;

[0078] S303: Increase the opening degree of the electronic expansion valve.

[0079] In S300, after controlling the drain valve to close, that is, after executing S202, the first refrigerant temperature at the outlet of the electronic expansion valve is obtained through the above-mentioned second temperature sensor.

[0080] In S301, based on the first refrigerant temperature obtained in S300, determine whether the first refrigerant temperature is greater than or equal to the second preset temperature.

[0081] If the first refrigerant temperature is greater than or equal to the second preset temperature, for example, the first refrigerant temperature is 11°C and the second preset temperature is 10°C, it indicates that the refrigerant temperature is more appropriate at this time, the outlet air temperature of the air conditioner will not be too low, and the evaporator will not frost. At this time, the opening degree of the electronic expansion valve is controlled to remain unchanged, that is, execute S302.

[0082] If the first refrigerant temperature is less than the second preset temperature, for example, the first refrigerant temperature is 8°C and the second preset temperature is 10°C, it indicates that the refrigerant temperature is too low at this time, the subcooling degree of the refrigerant is too high, which will cause the outlet air temperature of the air conditioner to be too low or the evaporator to frost. At this time, the opening degree of the electronic expansion valve is increased, that is, execute S303. By increasing the opening degree of the electronic expansion valve to increase the refrigerant flow rate, it is possible to reduce the amount of cold that can be obtained per unit volume of the refrigerant per unit time, and thus achieve the purpose of appropriately increasing the refrigerant temperature.

[0083] It should be noted that the increase in the opening degree of the electronic expansion valve is based on the magnitude of the first refrigerant temperature. If the first refrigerant temperature is less than the second preset temperature, the opening degree of the electronic expansion valve is continuously increased. If the first refrigerant temperature is greater than or equal to the second preset temperature, the opening degree of the electronic expansion valve is no longer increased, and the current opening degree of the electronic expansion valve is maintained unchanged. The increase amplitude of the opening degree of the electronic expansion valve can be to increase a fixed opening degree each time. For example, the opening degree is increased by 5% each time, etc. In order to ensure the stability of the operation of the wall-mounted air conditioner, after increasing the opening degree of the electronic expansion valve each time, there is an interval of a period of time before adjusting the opening degree of the electronic expansion valve again. Of course, the opening degree of the electronic expansion valve increased each time can also be different. Without departing from the principle of the present application, those skilled in the art can flexibly select the specific manner of increasing the opening degree of the electronic expansion valve according to the specific application scenario, as long as it can ensure the stable operation of the wall-mounted air conditioner while increasing the opening degree of the electronic expansion valve.

[0084] Through the above control method, when the refrigerant temperature is appropriate, the opening degree of the electronic expansion valve is kept unchanged. When the refrigerant temperature is on the low side, the opening degree of the electronic expansion valve is increased in order to increase the temperature of the refrigerant, so that the temperature of the refrigerant can be better controlled within a more appropriate range and the temperature of the indoor space can be better reduced.

[0085] It should be noted that after executing S202, it is also possible not to further adjust the opening degree of the electronic expansion valve according to the first refrigerant temperature at the outlet of the electronic expansion valve.

[0086] As Figure 7 shown, in a possible implementation manner, the control method of the present invention further includes:

[0087] S400: After increasing the opening degree of the electronic expansion valve to the maximum opening degree, obtain the second refrigerant temperature at the outlet of the electronic expansion valve;

[0088] S401: After obtaining the second refrigerant temperature for the first preset duration, obtain the third refrigerant temperature at the outlet of the electronic expansion valve again;

[0089] S402: Determine whether the second refrigerant temperature is greater than the third refrigerant temperature. If so, execute S403; if not, execute S407;

[0090] S403: Obtain the fourth refrigerant temperature at the outlet of the electronic expansion valve;

[0091] S404: Determine whether the fourth refrigerant temperature is greater than or equal to the third preset temperature. If so, execute S405; if not, execute S406;

[0092] S405: Control the drain valve to remain in the closed state;

[0093] S406: Control the drain valve to open;

[0094] S407: Control the drain valve to remain closed;

[0095] In S400, after the opening degree of the electronic expansion valve increases to the maximum opening degree, the second refrigerant temperature at the outlet of the electronic expansion valve is obtained through the above-mentioned second temperature sensor.

[0096] In S401, after obtaining the second refrigerant temperature for the first preset duration, for example, the first preset duration is 5 minutes, that is, after obtaining the second refrigerant temperature for 5 minutes, the third refrigerant temperature at the outlet of the electronic expansion valve is obtained again through the above-mentioned second temperature sensor.

[0097] In S402, based on the second refrigerant temperature and the third refrigerant temperature obtained in the above S400 and S401, it is judged whether the second refrigerant temperature is greater than the third refrigerant temperature.

[0098] If the second refrigerant temperature is less than the third refrigerant temperature, for example, the second refrigerant temperature is 9°C and the third refrigerant temperature is 10°C, it indicates that the refrigerant temperature at the outlet of the electronic expansion valve is on the rise. This also means that by increasing the opening degree of the electronic expansion valve, the temperature of the refrigerant can be effectively increased, and there is no need to take other means to increase the temperature of the refrigerant. At this time, the drain valve is controlled to remain closed, that is, S407 is executed.

[0099] If the second refrigerant temperature is greater than the third refrigerant temperature, for example, the second refrigerant temperature is 9°C and the third refrigerant temperature is 8°C, it indicates that the refrigerant temperature at the outlet of the electronic expansion valve is still low and on the decline. At this time, the fourth refrigerant temperature at the outlet of the electronic expansion valve is further obtained through the above-mentioned second temperature sensor, that is, S403 is executed.

[0100] In S404, based on the fourth refrigerant temperature obtained in the above S403, it is judged whether the fourth refrigerant temperature is greater than or equal to the third preset temperature.

[0101] If the fourth refrigerant temperature is greater than or equal to the third preset temperature, for example, the fourth refrigerant temperature is 10°C and the third preset temperature is 8°C, it indicates that although the temperature of the refrigerant is on the decline at present, the temperature of the refrigerant is not too low, the outlet air temperature will not be too low, and basically no frosting problem will occur in the evaporator. At this time, the drain valve is controlled to remain closed, that is, S405 is executed. Keep the current operating state unchanged and continue to reduce the temperature of the refrigerant through the subcooler.

[0102] If the temperature of the fourth refrigerant is less than the third preset temperature, for example, the temperature of the fourth refrigerant is 7°C and the third preset temperature is 8°C, it indicates that the current temperature of the refrigerant is still relatively low, and there are problems such as too low air outlet temperature or frosting of the evaporator. At this time, the drain valve is controlled to open, that is, S406 is executed. The temperature of the refrigerant is no longer reduced by the condensed water in the sub-cooler, in order to increase the temperature of the refrigerant.

[0103] Through the above control method, the temperature of the refrigerant can be controlled within a more appropriate range, so as to better adjust the temperature of the indoor space.

[0104] It should be noted that after the opening degree of the electronic expansion valve is increased to the maximum opening degree, it is also possible not to further control the opening or closing of the drain valve according to the change trend of the refrigerant temperature at the outlet of the electronic expansion valve. When the refrigerant temperature at the outlet of the electronic expansion valve is on a downward trend, it is also possible not to further control the opening or closing of the drain valve according to the magnitude of the fourth refrigerant temperature at the outlet of the electronic expansion valve.

[0105] As Figure 8 shown, in a possible implementation manner, the control method of the present invention further includes:

[0106] S500: After controlling the drain valve to open for a second preset duration, the fifth refrigerant temperature at the outlet of the electronic expansion valve is obtained again;

[0107] S501: Determine whether the fifth refrigerant temperature is greater than or equal to the fourth preset temperature. If so, execute S502; if not, execute S503;

[0108] S502: Control the drain valve to close;

[0109] S503: Control the drain valve to remain open;

[0110] In S500, after controlling the drain valve to open for a second preset duration, that is, after executing S406 for a second preset duration, for example, the second preset duration is 5 minutes. After executing S406 for 5 minutes, since the temperature of the refrigerant is no longer reduced by the condensed water in the sub-cooler, the temperature of the refrigerant will increase accordingly. At this time, the fifth refrigerant temperature at the outlet of the electronic expansion valve is obtained again through the above-mentioned second temperature sensor.

[0111] In S501, based on the fifth refrigerant temperature obtained in the above S500, it is determined whether the fifth refrigerant temperature is greater than or equal to the fourth preset temperature.

[0112] If the temperature of the fifth refrigerant is greater than or equal to the fourth preset temperature, for example, the temperature of the fifth refrigerant is 12 °C and the fourth preset temperature is 10 °C, it indicates that the temperature of the refrigerant has risen to a relatively appropriate temperature. If it continues to operate in the current state, the temperature of the refrigerant will continue to rise, and the cooling capacity provided by the refrigerant will decrease. At this time, condensate water is required to provide subcooling for the refrigerant, so the drain valve is controlled to close, that is, S502 is executed.

[0113] If the temperature of the fifth refrigerant is less than the fourth preset temperature, for example, the temperature of the fifth refrigerant is 9 °C and the fourth preset temperature is 10 °C, it indicates that the temperature of the refrigerant is still relatively low. At this time, the drain valve is controlled to remain open, that is, S503 is executed.

[0114] Through the above control method, the temperature of the refrigerant can be controlled within a relatively appropriate range, avoiding the situation that the outlet air temperature is too high due to too high refrigerant temperature, which may lead to failure to meet the cooling demand, or too low outlet air temperature due to too low refrigerant temperature, or even frosting of the evaporator.

[0115] If the operating mode of the air conditioner is the dehumidification mode, then regardless of the indoor and outdoor ambient temperatures, subcooling is first provided by condensate water, that is, the drain valve is controlled to close, so that condensate water can accumulate in the rechiller, and the temperature of the refrigerant is further reduced by the condensate water, so as to remove the moisture in the indoor air as soon as possible and improve the user experience. The following will refer to Figures 9 to 10 to illustrate a possible implementation manner of the control method when the operating mode of the wall-mounted air conditioner of the present invention is the dehumidification mode.

[0116] As Figure 9 shown, in a possible implementation manner, the control method of the present invention further includes:

[0117] S600: In the dehumidification mode, after controlling the drain valve to close for a third preset duration, obtain the temperature of the sixth refrigerant at the outlet of the throttling device;

[0118] S601: Determine whether the temperature of the sixth refrigerant is greater than or equal to the fifth preset temperature. If so, execute S602; if not, execute S603;

[0119] S602: Control the drain valve to remain closed;

[0120] S603: Control the drain valve to open.

[0121] In S600, in the dehumidification mode, after controlling the drain valve to close for a third preset duration, for example, the third preset duration is 3 min, that is, after controlling the drain valve to close for 3 min, the temperature of the sixth refrigerant at the outlet of the electronic expansion valve is obtained by the above-mentioned second temperature sensor.

[0122] In S601, based on the sixth refrigerant temperature obtained in the above S600, it is determined whether the sixth refrigerant temperature is greater than or equal to the fifth preset temperature.

[0123] If the sixth refrigerant temperature is greater than or equal to the fifth preset temperature, for example, the sixth refrigerant temperature is 10 °C and the fifth preset temperature is 8 °C. This indicates that the current refrigerant temperature is relatively appropriate. At this time, the drain valve is controlled to remain closed, that is, S602 is executed. The temperature of the refrigerant is continuously adjusted by the condensed water in the rechiller to ensure the dehumidification effect.

[0124] If the sixth refrigerant temperature is less than the fifth preset temperature, for example, the sixth refrigerant temperature is 7 °C and the fifth preset temperature is 8 °C. This indicates that the refrigerant temperature is too low and it is not possible or necessary to further reduce the refrigerant temperature by the condensed water in the rechiller. At this time, the drain valve is controlled to open, that is, S603 is executed, and the condensed water in the rechiller is drained to prevent the outlet air temperature from being too low or the evaporator from frosting.

[0125] Through the above control method, in the dehumidification mode, after the drain valve is controlled to close for the third preset duration, the opening or closing of the drain valve is controlled according to the temperature of the refrigerant at the outlet of the throttling device, so that while ensuring the dehumidification effect, the occurrence of situations such as too low outlet air temperature or evaporator frosting can be avoided, improving the user experience.

[0126] As Figure 10 shown, in a possible implementation manner, the control method of the present invention further includes:

[0127] S700: After controlling the drain valve to open for the fourth preset duration, the seventh refrigerant temperature at the outlet of the throttling device is obtained again;

[0128] S701: Determine whether the seventh refrigerant temperature is greater than or equal to the sixth preset temperature. If so, execute S702; if not, execute S703;

[0129] S702: Control the drain valve to close;

[0130] S703: Control the drain valve to remain open.

[0131] In S700, after controlling the drain valve to open for the fourth preset duration, that is, after executing S603 for the fourth preset duration, for example, the fourth preset duration is 3 min, that is, 3 min after executing S703, since the temperature of the refrigerant is no longer reduced by the condensed water in the rechiller, the temperature of the refrigerant will increase accordingly. At this time, the seventh refrigerant temperature at the outlet of the electronic expansion valve is obtained again through the above second temperature sensor.

[0132] In S701, based on the seventh refrigerant temperature obtained in S700, it is determined whether the seventh refrigerant temperature is greater than or equal to the sixth preset temperature.

[0133] If the temperature of the seventh refrigerant is greater than or equal to the sixth preset temperature, for example, the temperature of the seventh refrigerant is 14 °C and the sixth preset temperature is 10 °C, it indicates that the temperature of the refrigerant at the outlet of the throttling device is a bit high. If its temperature is not reduced, it may continue to rise, which may lead to a high temperature at the evaporator and ineffective dehumidification. At this time, the drain valve is controlled to close, that is, S702 is executed, and the temperature of the refrigerant is reduced by the condensed water in the rechiller.

[0134] If the temperature of the seventh refrigerant is less than the sixth preset temperature, for example, the temperature of the seventh refrigerant is 7 °C and the sixth preset temperature is 10 °C, it indicates that the temperature of the refrigerant is still relatively low. At this time, the drain valve is controlled to remain open, that is, S703 is executed, in order to increase the temperature of the refrigerant.

[0135] Through the above control method, after the drain valve is controlled to open for the fourth preset duration, that is, after S603 is executed for the fourth preset duration, the opening or closing of the drain valve is controlled according to the temperature at the outlet of the throttling device, so that the temperature of the refrigerant can be controlled within an appropriate range and the dehumidification efficiency can be improved.

[0136] It should be noted that the specific values of the above first refrigerant temperature, second refrigerant temperature, third refrigerant temperature, fourth refrigerant temperature, fifth refrigerant temperature, sixth refrigerant temperature, seventh refrigerant temperature, first preset temperature, second preset temperature, third preset temperature, fourth preset temperature, fifth preset temperature, sixth preset temperature, first preset duration, second preset duration, third preset duration, and fourth preset duration are only exemplary descriptions and are not restrictive. Without departing from the principle of the present application, those skilled in the art can flexibly select the specific values of the above refrigerant temperatures, preset temperatures, and preset durations according to the specific application scenarios, as long as the stable operation of the wall-mounted air conditioner can be ensured while better adjusting the temperature and humidity of the indoor space.

[0137] In summary, in the present invention, by controlling the opening or closing of the drain valve according to the operating mode of the wall-mounted air conditioner, that is, controlling whether condensate water is stored in the subcooler, it is possible to determine whether to further reduce the temperature of the refrigerant by the condensate water as needed, so as to better adjust the temperature of the refrigerant, and further better adjust the temperature and humidity of the indoor space. When the wall-mounted air conditioner operates in the cooling mode, first control the opening or closing of the drain valve according to the outdoor temperature. After controlling the drain valve to close, control the opening degree of the electronic expansion valve according to the magnitude of the first refrigerant temperature at the outlet of the electronic expansion valve to prevent the temperature of the refrigerant from being too low. After increasing the opening degree of the electronic expansion valve to the maximum opening degree, according to the change trend of the refrigerant temperature at the outlet of the electronic expansion valve, when the refrigerant temperature is in a downward trend, control the opening or closing of the drain valve according to the magnitude of the fourth refrigerant temperature at the outlet of the electronic expansion valve, and when the refrigerant temperature is in an upward trend, control the drain valve to remain closed. After controlling the drain valve to open for a second preset duration, if the fifth refrigerant temperature is greater than or equal to the fourth preset temperature, control the drain valve to close. Through such a control method, the temperature of the refrigerant can be controlled within a more appropriate range, so as to better adjust the temperature of the indoor space. When the operating mode of the wall-mounted air conditioner is the dehumidification mode, control the drain valve to close to quickly remove the moisture in the indoor air and improve the user experience. After controlling the drain valve to close for a third preset duration, control the opening or closing of the drain valve according to the magnitude of the sixth refrigerant temperature at the outlet of the throttling device, so as to avoid the occurrence of situations such as too low outlet air temperature or frosting of the evaporator while ensuring the dehumidification effect. After controlling the drain valve to open for a fourth preset duration, control the opening or closing of the drain valve according to the magnitude of the seventh refrigerant temperature at the outlet of the throttling device, so as to control the refrigerant temperature within an appropriate range and improve the dehumidification efficiency.

[0138] Although the above steps are described in the above sequential order 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, and these simple changes are all within the protection scope of this application.

[0139] So far, the technical solution of the present invention has been described in combination with the preferred embodiments shown in the 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 all fall within the protection scope of the present invention.

Claims

1. A control method for an air conditioner, characterized in that The air conditioner includes a compressor, a condenser, a throttling device, and an evaporator. The refrigerant circulates among the compressor, the condenser, the throttling device, and the evaporator. The air conditioner further includes a sub-cooler, which is disposed between the condenser and the throttling device. Condensate water can be stored in the sub-cooler. At least a part of the refrigerant pipeline located between the condenser and the throttling device is disposed in the sub-cooler. A drain valve is provided on the sub-cooler. When the drain valve is set to be open, it can allow the condensate water in the sub-cooler to be discharged. The control method includes: Obtaining the operating mode of the air conditioner; Controlling the drain valve to open or close according to the operating mode; Wherein, if the operating mode is the cooling mode, the control method further includes: Obtaining the outdoor temperature; Comparing the size of the outdoor temperature with a first preset temperature; If the outdoor temperature is less than the first preset temperature, controlling the drain valve to open; If the outdoor temperature is greater than or equal to the first preset temperature, controlling the drain valve to close; Wherein, the throttling device is an electronic expansion valve, and the control method further includes: After controlling the drain valve to close, obtaining the first refrigerant temperature at the outlet of the electronic expansion valve; Comparing the size of the first refrigerant temperature with a second preset temperature; If the first refrigerant temperature is greater than or equal to the second preset temperature, controlling the opening degree of the electronic expansion valve to remain unchanged; If the first refrigerant temperature is less than the second preset temperature, increasing the opening degree of the electronic expansion valve; Wherein, if the operating mode is the dehumidification mode, the control method further includes: Controlling the drain valve to close.

2. The control method according to claim 1, wherein The control method further includes: After increasing the opening degree of the electronic expansion valve to the maximum opening degree, obtaining the second refrigerant temperature at the outlet of the electronic expansion valve; After obtaining the second refrigerant temperature for a first preset duration, obtaining the third refrigerant temperature at the outlet of the electronic expansion valve again; Judging whether the refrigerant temperature at the outlet of the electronic expansion valve is in a downward trend according to the size of the second refrigerant temperature and the third refrigerant temperature; Selectively controlling the drain valve to remain in the closed state according to the judgment result.

3. The control method according to claim 2, wherein The step of "selectively controlling the drain valve to remain in the closed state according to the judgment result" specifically includes: If the refrigerant temperature at the outlet of the electronic expansion valve is in a downward trend, further obtaining the fourth refrigerant temperature at the outlet of the electronic expansion valve, and selectively controlling the drain valve to remain in the closed state according to the size of the fourth refrigerant temperature; If the refrigerant temperature at the outlet of the electronic expansion valve is in an upward trend, controlling the drain valve to remain in the closed state.

4. The control method according to claim 3, wherein, The step of "selectively controlling the drain valve to remain in the closed state according to the size of the fourth refrigerant temperature" specifically includes: Comparing the size of the fourth refrigerant temperature with a third preset temperature; If the fourth refrigerant temperature is less than the third preset temperature, controlling the drain valve to open; If the fourth refrigerant temperature is greater than or equal to the third preset temperature, controlling the drain valve to remain in the closed state.

5. The control method according to claim 4, wherein The control method further includes: After controlling the water discharge valve to open for a second preset duration, obtaining the fifth refrigerant temperature at the outlet of the electronic expansion valve again; Comparing the magnitude of the fifth refrigerant temperature with a fourth preset temperature; If the fifth refrigerant temperature is greater than or equal to the fourth preset temperature, controlling the water discharge valve to close.

6. The control method according to claim 1, wherein The control method further includes: After controlling the water discharge valve to close for a third preset duration, obtaining the sixth refrigerant temperature at the outlet of the throttling device; Comparing the magnitude of the sixth refrigerant temperature with a fifth preset temperature; If the sixth refrigerant temperature is less than the fifth preset temperature, controlling the water discharge valve to open; If the sixth refrigerant temperature is greater than or equal to the fifth preset temperature, controlling the water discharge valve to continue to maintain a closed state.

7. The control method according to claim 6, characterized in that The control method further includes: After controlling the water discharge valve to open for a fourth preset duration, obtaining the seventh refrigerant temperature at the outlet of the throttling device again; Comparing the magnitude of the seventh refrigerant temperature with a sixth preset temperature; If the seventh refrigerant temperature is less than the sixth preset temperature, controlling the water discharge valve to continue to maintain an open state; If the seventh refrigerant temperature is greater than or equal to the sixth preset temperature, controlling the water discharge valve to close.

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