Air conditioner and control method thereof

Abstract

The application discloses an air conditioner and a control method thereof. The air conditioner comprises a liquid accumulator with a cavity, which is connected in series between an outdoor heat exchanger and a throttling device. A bypass inlet is arranged on the liquid accumulator and connected with a compressor exhaust port. A controller is used to control the opening and closing of a bypass valve. When the controller controls the bypass valve to open, high-temperature and high-pressure refrigerant discharged from the compressor exhaust port is introduced into the cavity of the liquid accumulator through the bypass valve and the bypass inlet, and is mixed with refrigerant from the outdoor heat exchanger in the cavity, so that the pressure of the refrigerant in the liquid accumulator is increased. Since the liquid accumulator is connected in series in a refrigerant circulation loop and is located on the side of the throttling device, the increase of the pressure of the refrigerant in the liquid accumulator increases the pressure difference before and after the throttling device, and sufficient refrigerant circulation power can be provided for the start of the compressor, so that the problem of insufficient pressure difference caused by excessively low condensing pressure during the start of refrigeration under low-temperature working conditions is solved, and the stability and reliability of the start of refrigeration under low-temperature working conditions are improved.

Description

Technical Field

[0001] This application relates to the field of air conditioning technology, and in particular to an air conditioner and its control method. Background Technology

[0002] An air conditioner's refrigeration system typically consists of a compressor, an outdoor heat exchanger, a throttling device, and an indoor heat exchanger, connected sequentially via refrigerant piping to form a refrigerant circulation loop. In cooling mode, the compressor compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant. This high-temperature, high-pressure gaseous refrigerant enters the outdoor heat exchanger to exchange heat with the outdoor environment and condenses into a high-pressure liquid refrigerant. The high-pressure liquid refrigerant then passes through the throttling device to reduce its pressure before entering the indoor heat exchanger. In the indoor heat exchanger, it absorbs heat and evaporates into a low-temperature, low-pressure gaseous refrigerant. This low-temperature, low-pressure gaseous refrigerant then flows back to the compressor, thus completing the refrigeration cycle.

[0003] As the application scenarios of air conditioners continue to expand, users' demand for cooling performance under low-temperature conditions is increasing. For example, in regions like Europe and Russia, when outdoor temperatures are very low in winter, even below zero, indoor heating is often achieved through centralized natural gas heating or fireplaces, resulting in excessively high indoor temperatures that require cooling to achieve a comfortable temperature. However, current air conditioner cooling modes are designed for typical environments with outdoor temperatures above 15°C. When the outdoor temperature is low, the temperature difference between the refrigerant in the outdoor heat exchanger and the external environment decreases, leading to a corresponding drop in the condensation temperature and pressure of the refrigerant in the outdoor heat exchanger. Since there is a definite correlation between the refrigerant's saturation temperature and saturation pressure, the decrease in condensation pressure directly results in insufficient pressure difference across the throttling device. During the initial compressor startup, insufficient refrigerant circulation power in the refrigerant loop prevents effective heat exchange, and the indoor heat exchanger fails to absorb heat from the room in time. This causes a continuous drop in compressor suction pressure, frequently triggering low-pressure protection, resulting in cooling startup failure or unstable operation, severely impacting the user experience.

[0004] Therefore, it is necessary to optimize air conditioners to meet the cooling operation requirements under low-temperature conditions. Summary of the Invention

[0005] To address the aforementioned issues, this application provides an air conditioner comprising a compressor, an outdoor heat exchanger, an indoor heat exchanger, a throttling device, a liquid receiver, a bypass valve, and a controller, wherein the compressor, the outdoor heat exchanger, the throttling device, and the indoor heat exchanger are sequentially connected to form a refrigerant circulation loop.

[0006] The receiver is connected in series in the refrigerant circulation loop and located between the outdoor heat exchanger and the throttling device. The receiver has a chamber and a refrigerant inlet, a refrigerant outlet, and a bypass inlet communicating with the chamber. The refrigerant inlet is connected to the outdoor heat exchanger, and the refrigerant outlet is connected to the throttling device. The chamber is used to contain the refrigerant entering through the refrigerant inlet and the bypass inlet. One end of the bypass valve is connected to the exhaust port of the compressor, and the other end of the bypass valve is connected to the bypass inlet of the receiver. When the bypass valve is open, the exhaust port of the compressor communicates with the bypass inlet. The controller is electrically connected to the bypass valve and is used to control the bypass valve to open so that the refrigerant discharged from the exhaust port of the compressor is introduced into the receiver through the bypass valve and the bypass inlet, or to control the bypass valve to close.

[0007] Thus, in the above technical solution, a liquid receiver with a chamber is connected in series between the outdoor heat exchanger and the throttling device. A bypass inlet connected to the compressor discharge port is provided on the liquid receiver, and a controller is used to control the opening and closing of the bypass valve. When the controller controls the bypass valve to open, the high-temperature and high-pressure refrigerant discharged from the compressor discharge port can be introduced into the liquid receiver chamber through the bypass valve and the bypass inlet, mixing with the refrigerant from the outdoor heat exchanger inside the chamber, thereby increasing the pressure of the refrigerant in the liquid receiver. Since the liquid receiver is connected in series in the refrigerant circulation loop and located on one side of the throttling device, the increase in refrigerant pressure in the liquid receiver increases the pressure difference before and after the throttling device, which can provide sufficient refrigerant circulation power for compressor startup. This effectively solves the problem of insufficient pressure difference caused by excessively low condensing pressure during refrigeration startup under low-temperature conditions, improves the defect of frequent low-pressure protection triggering during the refrigeration startup phase, and improves the stability and reliability of refrigeration startup under low-temperature conditions.

[0008] In some embodiments of this application, the liquid reservoir includes a liquid reservoir body having the chamber, and a refrigerant outlet pipe is provided on the liquid reservoir body. The refrigerant outlet pipe is connected to the throttling device and forms the refrigerant outlet. The refrigerant outlet pipe extends into the chamber, and the refrigerant outlet is located at the bottom of the chamber and has a gap between it and the bottom wall of the chamber.

[0009] In the above technical solution, by setting a liquid storage tank body with a chamber and setting a refrigerant outlet pipe extending into the chamber on the liquid storage tank body, the refrigerant outlet is located at the bottom of the chamber and there is a gap between it and the bottom wall. This ensures that the liquid refrigerant in the chamber can flow out smoothly through the bottom refrigerant outlet first, preventing gaseous refrigerant from entering the throttling device. At the same time, the gap structure prevents the refrigerant outlet from sticking to the wall and causing refrigerant stagnation, ensuring that even when the liquid level is low, the liquid refrigerant can still flow to the throttling device.

[0010] In some embodiments of this application, the refrigerant inlet is located at the top of the chamber; and / or, the bypass air inlet is located at the top of the chamber.

[0011] In the above technical solution, by placing the refrigerant inlet and bypass inlet at the top of the chamber, the gas-liquid mixed refrigerant from the outdoor heat exchanger and the high-temperature, high-pressure gaseous refrigerant from the compressor exhaust port both enter from the upper part of the chamber. The liquid refrigerant naturally settles and accumulates at the lower part of the chamber due to gravity, while the gaseous refrigerant is located at the upper part, achieving efficient gas-liquid separation. At the same time, after the high-temperature gas enters from above, it forms natural convection with the liquid refrigerant at the bottom, resulting in a large contact area, sufficient sensible heat exchange, rapid temperature rise of the liquid refrigerant, and synchronous increase in saturation pressure, thereby quickly establishing the pressure difference before and after the throttling device.

[0012] In some embodiments of this application, the controller is configured to: control the bypass valve to open when the air conditioner is operating in cooling mode and the outdoor ambient temperature where the air conditioner is located is detected to be below a first temperature threshold and / or the coil temperature of the outdoor heat exchanger is detected to be below a second temperature threshold.

[0013] In the above technical solution, by using dual temperature parameters to determine low-temperature operating conditions, the actual operating status of the air conditioner can be identified more reliably than a single parameter, avoiding the bypass valve from being falsely triggered due to short-term fluctuations in ambient temperature.

[0014] In some embodiments of this application, the air conditioner further includes an ambient temperature sensor and a coil temperature sensor. The ambient temperature sensor is electrically connected to the controller and is used to detect the outdoor ambient temperature where the air conditioner is located and send it to the controller. The coil temperature sensor is electrically connected to the controller and is used to detect the coil temperature of the outdoor heat exchanger and send it to the controller.

[0015] In the above technical solution, by setting an ambient temperature sensor and a coil temperature sensor, the outdoor ambient temperature and the coil temperature are detected in real time and sent to the controller. This enables the controller to accurately determine whether the preset conditions are met based on real-time data, avoiding startup failure caused by manual judgment or delayed detection.

[0016] In some embodiments of this application, the controller is configured to: control the bypass valve to close when the air conditioner is operating in heating mode; when the bypass valve is closed, the exhaust port of the compressor is not connected to the bypass intake port.

[0017] In the above technical solution, by controlling the bypass valve to close in heating mode, the compressor exhaust port and the bypass intake port are not connected, ensuring that all compressor exhaust flows to the indoor heat exchanger in heating mode. This avoids the refrigerant bypassing to the liquid receiver located on the outdoor side, which would cause heat loss and excessive pressure on the high-pressure side of the refrigerant circulation loop, thus deviating from the normal operating range and ensuring a complete and efficient heating cycle.

[0018] This application also provides a control method for an air conditioner, the air conditioner as described above, the control method comprising: when the air conditioner is operating in cooling mode, acquiring the outdoor ambient temperature and / or the coil temperature of the outdoor heat exchanger; when the outdoor ambient temperature is below a first temperature threshold and / or the coil temperature of the outdoor heat exchanger is below a second temperature threshold, controlling the bypass valve to open, so that the refrigerant discharged from the compressor's exhaust port is introduced into the liquid receiver through the bypass valve and the bypass inlet.

[0019] In the above technical solution, by increasing the refrigerant pressure in the receiver, the pressure difference before and after the throttling device is increased, which can provide sufficient refrigerant circulation power for compressor startup. This effectively solves the problem of insufficient pressure difference caused by low condensing pressure during refrigeration startup under low temperature conditions, improves the defect of frequent low-pressure protection triggering during refrigeration startup, and enhances the stability and reliability of refrigeration startup under low temperature conditions.

[0020] In some embodiments of this application, the control method further includes: controlling the bypass valve to close when the coil temperature of the outdoor heat exchanger reaches or exceeds a third temperature threshold; wherein the third temperature threshold is equal to the sum of the second temperature threshold and the first temperature difference, and the first temperature difference is greater than zero.

[0021] In the above technical solution, the third temperature threshold is higher than the second temperature threshold, forming a temperature hysteresis (first temperature difference). When the coil temperature rises from the low temperature to the second temperature threshold, the bypass valve will not close immediately, but will remain open until the coil temperature rises to the third temperature threshold. This hysteresis control mechanism avoids frequent opening and closing of the bypass valve when the coil temperature fluctuates around the second temperature threshold, improving the operational stability of the air conditioner. At the same time, when the coil temperature has fully risen above the third temperature threshold, it indicates that the refrigerant circulation loop has entered normal operating condition. At this time, closing the bypass valve allows the refrigerant circulation loop to maintain a sufficient pressure difference through its own circulation, avoiding premature closure that could lead to insufficient pressure difference and startup failure.

[0022] In some embodiments of this application, the control method further includes: when the air conditioner is operating in heating mode, controlling the bypass valve to close so that the exhaust port of the compressor is not connected to the bypass intake port.

[0023] In the above technical solution, by controlling the bypass valve to close in heating mode, the compressor exhaust port and the bypass intake port are not connected, ensuring that all compressor exhaust flows to the indoor heat exchanger in heating mode. This avoids the refrigerant bypassing to the liquid receiver located on the outdoor side, which would cause heat loss and excessive pressure on the high-pressure side of the refrigerant circulation loop, thus deviating from the normal operating range and ensuring a complete and efficient heating cycle.

[0024] In some embodiments of this application, the control method further includes: when a working mode switching command or a shutdown command is received, controlling the bypass valve to close, and then executing the working mode switching command or the shutdown command.

[0025] In the above technical solution, when the air conditioner receives a shutdown command or mode switching command, regardless of the bypass valve's state, it first controls the bypass valve to close before executing the shutdown or mode switching. This control method ensures that the bypass valve remains closed during shutdown or mode switching, without affecting the air conditioner's normal cooling or heating functions. It also prevents the refrigerant circulation loop pressure from deviating from the normal operating range due to abnormal bypass valve conduction, thus improving the air conditioner's operational safety. Simultaneously, ensuring the bypass valve is closed before shutdown ensures the refrigerant circulation loop starts from its normal initial state upon the next startup, preventing abnormal refrigerant circulation loop operation when the bypass valve is open, protecting the compressor and extending its service life.

[0026] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the specification, serve to explain the principles of this application.

[0028] Figure 1 A schematic diagram of the refrigerant circulation loop structure of an air conditioner according to an embodiment of this application is shown.

[0029] Figure 2 A block diagram of an air conditioner electronic control system according to an embodiment of this application is shown.

[0030] Figure 3 A flowchart of a control method for an air conditioner according to an embodiment of this application is shown.

[0031] Figure 4 A flowchart of a control method for an air conditioner according to another embodiment of this application is shown.

[0032] Figure 5 A flowchart of a control method for an air conditioner according to another embodiment of this application is shown.

[0033] The annotations in the attached figures are explained as follows: 1. Compressor; 2. Outdoor heat exchanger; 3. Indoor heat exchanger; 4. Throttling device; 5. Receiver; 51. Chamber; 52. Refrigerant inlet; 53. Refrigerant outlet; 54. Bypass inlet; 55. Receiver body; 56. Refrigerant outlet pipe; 6. Bypass valve; 61. Bypass pipeline; 7. Controller; 81. Ambient temperature sensor; 82. Coil temperature sensor. Detailed Implementation

[0034] To make the objectives, implementation methods and advantages of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the described exemplary embodiments are only some embodiments of this application, and not all embodiments.

[0035] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0036] In the description of this application, it should be understood that the terms "inner", "outer", "top", "bottom", "upper", "lower", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0037] The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0038] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connect," "link," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0040] In related technologies, air conditioners frequently trigger low-pressure protection when cooling in low-temperature environments, leading to cooling start-up failure or unstable operation. This is because the air conditioner's cooling mode is designed for conventional use environments with outdoor ambient temperatures above 15°C. When the outdoor ambient temperature is low, the temperature difference between the refrigerant in the outdoor heat exchanger and the outside environment decreases, and the condensing temperature and condensing pressure of the refrigerant in the outdoor heat exchanger decrease accordingly. Since there is a definite correlation between the saturation temperature and saturation pressure of the refrigerant, the decrease in condensing pressure directly leads to insufficient pressure difference before and after the throttling device, preventing the refrigerant from effectively circulating and exchanging heat. The indoor heat exchanger fails to absorb heat from the room in time, and the compressor suction pressure continues to drop, thus frequently triggering low-pressure protection.

[0041] In view of this, this application connects a chambered receiver in series between the outdoor heat exchanger and the throttling device, and provides a bypass inlet on the receiver connected to the compressor exhaust port. When the controller detects that preset conditions are met, it controls the bypass valve to open, allowing the high-temperature, high-pressure refrigerant discharged from the compressor exhaust port to enter the receiver chamber through the bypass valve and the bypass inlet, mixing with the refrigerant from the outdoor heat exchanger inside the chamber, thereby increasing the pressure of the refrigerant in the receiver. Since the receiver is connected in series in the refrigerant circulation loop and located on one side of the throttling device, the increase in refrigerant pressure in the receiver increases the pressure difference before and after the throttling device, providing sufficient refrigerant circulation power for compressor startup. This effectively solves the problem of insufficient pressure difference caused by excessively low condensing pressure during refrigeration startup under low-temperature conditions, improves the defect of frequent low-pressure protection triggering during refrigeration startup, and enhances the stability and reliability of refrigeration startup under low-temperature conditions.

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0043] The air conditioner disclosed in this application has a refrigerant circulation loop that circulates the refrigerant within a circuit consisting of a compressor, an outdoor heat exchanger, a throttling device, and an indoor heat exchanger, thereby performing a cooling / heating cycle. The cooling / heating cycle includes a series of processes involving compression, condensation, expansion, and evaporation. The compressor compresses the refrigerant gas at a high temperature and pressure and discharges the compressed refrigerant gas. The discharged refrigerant gas flows through a four-way valve, flowing into the outdoor heat exchanger in cooling mode and into the indoor heat exchanger in heating mode. The outdoor or indoor heat exchanger condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process. A throttling device, such as an electronic expansion valve, expands the high-temperature, high-pressure liquid refrigerant condensed in one heat exchanger (acting as a condenser) into a low-pressure liquid refrigerant. The other heat exchanger (acting as an evaporator) evaporates the refrigerant that expanded in the throttling device, returning the low-temperature, low-pressure refrigerant gas to the compressor, completing the entire cycle. The evaporation process achieves cooling or heating effects by utilizing the latent heat of refrigerant evaporation to exchange heat with the material being cooled or heated. Throughout the entire cooling / heating cycle, the air conditioner regulates the temperature of the indoor space.

[0044] The air conditioner described in this application can perform both cooling and heating functions. In cooling mode, the refrigerant, after being compressed by the compressor, flows sequentially through a four-way valve, outdoor heat exchanger, throttling device, and indoor heat exchanger, finally returning to the compressor through the four-way valve to complete the refrigeration cycle. In this mode, the outdoor heat exchanger functions as a condenser, and the indoor heat exchanger functions as an evaporator. In heating mode, the refrigerant flow is switched via the four-way valve. The refrigerant, after being compressed by the compressor, first flows sequentially through the indoor heat exchanger, throttling device, and outdoor heat exchanger, finally returning to the compressor through the four-way valve to complete the heating cycle. In this mode, the indoor heat exchanger functions as a condenser, and the outdoor heat exchanger functions as an evaporator.

[0045] Figure 1 A schematic diagram of the refrigerant circulation loop structure of an air conditioner according to an embodiment of this application is shown.

[0046] like Figure 1 As shown, the air conditioner includes a compressor 1, an outdoor heat exchanger 2, an indoor heat exchanger 3, and a throttling device 4. The following description, using the cooling mode as an example, illustrates the composition of the refrigerant circulation loop.

[0047] Compressor 1 has an exhaust port and an intake port. Compressor 1 is used to compress low-temperature, low-pressure gaseous refrigerant into high-temperature, high-pressure gaseous refrigerant, which is then discharged through the exhaust port. The intake port is used to draw in low-temperature, low-pressure gaseous refrigerant, allowing it to enter compressor 1 for compression.

[0048] The inlet of outdoor heat exchanger 2 is connected to the exhaust port of compressor 1, and the outlet of outdoor heat exchanger 2 is connected to the inlet of throttling device 4. In cooling mode, outdoor heat exchanger 2 functions as a condenser, where high-temperature, high-pressure gaseous refrigerant exchanges heat with the outdoor environment and condenses into high-pressure liquid refrigerant. Outdoor heat exchanger 2 typically includes heat exchange tubes and fins, and forced convection by a fan enhances the heat exchange effect. The coil temperature of outdoor heat exchanger 2 can be detected by a coil temperature sensor, reflecting the condensation state of the refrigerant within outdoor heat exchanger 2.

[0049] The inlet of the indoor heat exchanger 3 is connected to the outlet of the throttling device 4, and the outlet of the indoor heat exchanger 3 is connected to the suction port of the compressor 1. In cooling mode, the indoor heat exchanger 3 functions as an evaporator. The low-pressure liquid refrigerant, after being throttled and depressurized by the throttling device 4, absorbs heat and evaporates in the indoor heat exchanger 3, becoming a low-temperature, low-pressure gaseous refrigerant, thereby cooling the indoor space. The indoor heat exchanger 3 typically includes heat exchange tubes and fins, and the cooling capacity is delivered into the room via forced convection by a fan.

[0050] A throttling device 4 is installed between the outlet of the outdoor heat exchanger 2 and the inlet of the indoor heat exchanger 3. The throttling device 4 is used to reduce the pressure of the high-pressure liquid refrigerant, transforming it into a low-pressure liquid refrigerant before it enters the indoor heat exchanger 3. The throttling device 4 can be an electronic expansion valve, a capillary tube, or a thermostatic expansion valve, etc. In one embodiment, the throttling device 4 uses an electronic expansion valve, which controls the refrigerant flow rate by adjusting its opening to adapt to different operating conditions.

[0051] Compressor 1, outdoor heat exchanger 2, throttling device 4, and indoor heat exchanger 3 are connected sequentially to form a refrigerant circulation loop. Specifically, the discharge port of compressor 1 is connected to the inlet of outdoor heat exchanger 2, the outlet of outdoor heat exchanger 2 is connected to the inlet of throttling device 4, the outlet of throttling device 4 is connected to the inlet of indoor heat exchanger 3, and the outlet of indoor heat exchanger 3 is connected to the suction port of compressor 1. Under refrigeration conditions, the refrigerant circulates in this loop in the direction of compressor 1, outdoor heat exchanger 2, throttling device 4, indoor heat exchanger 3, and back to compressor 1.

[0052] In some embodiments, the air conditioner includes a receiver 5 and a bypass valve 6. The receiver 5 is connected in series in the refrigerant circulation loop and is located between the outlet of the outdoor heat exchanger 2 and the inlet of the throttling device 4. The receiver 5 has a chamber 51 and a refrigerant inlet 52, a refrigerant outlet 53, and a bypass inlet 54 communicating with the chamber 51. The refrigerant inlet 52 is connected to the outlet of the outdoor heat exchanger 2, and the refrigerant outlet 53 is connected to the inlet of the throttling device 4. The chamber 51 is used to contain the refrigerant entering through the refrigerant inlet 52 and the bypass inlet 54, providing a buffer and mixing space for the refrigerant from the outdoor heat exchanger 2 and the high-temperature, high-pressure refrigerant from the bypass valve 6.

[0053] In some embodiments, the reservoir 5 includes a reservoir body 55 having a chamber 51. The reservoir body 55 can be a sealed tank-like structure with a certain pressure-bearing capacity. The reservoir body 55 has multiple openings for a refrigerant inlet 52, a refrigerant outlet 53, and a bypass inlet 54. The refrigerant inlet 52, the refrigerant outlet 53, and the bypass inlet 54 all connect the chamber 51 to the outside, allowing the refrigerant to flow between the chamber 51 and the external pipeline.

[0054] In some embodiments, two openings of the reservoir body 55 further serve as a refrigerant inlet 52 and a bypass inlet 54, respectively. A refrigerant outlet pipe 56 is provided on the reservoir body 55, with one opening of the reservoir body 55 for the refrigerant outlet pipe 56 to be installed. The refrigerant outlet pipe 56 is connected to the inlet of the throttling device 4 to form a refrigerant outlet 53. The refrigerant outlet pipe 56 extends into the chamber 51, and the refrigerant outlet 53 is located at the bottom of the chamber 51 and has a gap between it and the bottom wall of the chamber 51.

[0055] This gap ensures that the liquid refrigerant in chamber 51 can flow to the refrigerant outlet 53, preventing the refrigerant from sticking to the wall and causing refrigerant stagnation or obstructed flow. At the same time, the refrigerant outlet 53 is located at the bottom of chamber 51, allowing the liquid refrigerant accumulated in chamber 51 to flow out preferentially through the refrigerant outlet 53, ensuring that the refrigerant entering the throttling device 4 is mainly in liquid form, thereby improving the throttling effect and cooling efficiency.

[0056] In some embodiments, the refrigerant inlet 52 is located at the top of the chamber 51. Gas-liquid mixed refrigerant from the outdoor heat exchanger 2 enters from the top of the chamber 51. The liquid refrigerant, due to its higher density, naturally sinks, while the gaseous refrigerant remains in the upper part of the chamber 51, achieving gas-liquid separation. The liquid refrigerant gradually accumulates in the lower part of the chamber 51 and eventually flows out through the refrigerant outlet 53 located at the bottom of the chamber 51.

[0057] In some embodiments, the bypass inlet 54 is located at the top of the chamber 51. When the bypass valve 6 is open, high-temperature, high-pressure gaseous refrigerant from the compressor 1 exhaust port enters from the top of the chamber 51, mixes with the gaseous refrigerant located in the upper part of the chamber 51, and forms convection with the liquid refrigerant accumulated in the lower part of the chamber 51. This results in a large contact area and sufficient sensible heat exchange. The high-temperature gaseous refrigerant transfers sensible heat to the liquid refrigerant, causing the liquid refrigerant temperature to rise and its saturation pressure to rise simultaneously. At the same time, the high-temperature gaseous refrigerant itself cools down, partially condensing into liquid and mixing with the existing liquid refrigerant. The overall increase in temperature and pressure of the refrigerant within the chamber 51 increases the pressure at the inlet of the throttling device 4, thereby increasing the pressure difference before and after the throttling device 4 and providing sufficient power for refrigerant circulation.

[0058] Both the refrigerant inlet 52 and the bypass inlet 54 are located at the top of the chamber 51, allowing the refrigerant from the outdoor heat exchanger 2 and the high-temperature, high-pressure refrigerant from the compressor 1 exhaust port to enter from the top of the chamber 51. This facilitates the initial mixing of the two airflows in the upper part of the chamber 51 before heat and mass exchange with the liquid refrigerant accumulated in the lower part. The refrigerant inlet 52 and the bypass inlet 54 can be located on the same or different side walls of the liquid receiver body 55, depending on the manufacturing process and piping layout requirements of the liquid receiver body 55.

[0059] One end of the bypass valve 6 is connected to the discharge port of the compressor 1, and the other end is connected to the bypass inlet 54 of the receiver 5. When the bypass valve 6 is open, the discharge port of the compressor 1 is connected to the bypass inlet 54, and the high-temperature and high-pressure refrigerant discharged by the compressor 1 can be introduced into the chamber 51 of the receiver 5 through the bypass valve 6 and the bypass inlet 54. When the bypass valve 6 is closed, the passage between the discharge port of the compressor 1 and the bypass inlet 54 is cut off, and the refrigerant cannot enter the receiver 5 through the bypass valve 6.

[0060] The bypass valve 6 can be a solenoid valve, an electric valve, or other controllable valve. In one embodiment, the bypass valve 6 is a solenoid valve, which offers fast response and high control precision. The bypass valve 6 is normally closed.

[0061] In some embodiments, one end of the bypass valve 6 is connected to the discharge port of the compressor 1 via a bypass pipe 61. The diameter of the bypass pipe 61 can be smaller than the diameter of the compressor 1 discharge pipe, thereby limiting the refrigerant flow to the receiver 5 and preventing insufficient flow in the normal refrigerant circulation loop due to the bypass of a large amount of high-temperature, high-pressure refrigerant. A flow regulating valve can also be further installed on the bypass pipe 61 to precisely control the flow of bypass refrigerant and adapt to different operating conditions.

[0062] Figure 2 A block diagram of an air conditioner electronic control system according to an embodiment of this application is shown.

[0063] like Figure 2 As shown, the air conditioner includes a controller 7, which is electrically connected to a bypass valve 6 and is used to control the opening and closing of the bypass valve 6. The controller 7 can be the main control board of the air conditioner or an independent control module, and has signal acquisition, logic judgment, and command output functions. When preset conditions are met, the controller 7 controls the bypass valve 6 to open, so that the refrigerant discharged from the exhaust port of the compressor 1 is introduced into the liquid receiver 5 through the bypass valve 6 and the bypass inlet 54.

[0064] The air conditioner also includes an ambient temperature sensor 81 and a coil temperature sensor 82. The ambient temperature sensor 81 is electrically connected to the controller 7 and is used to detect the outdoor ambient temperature where the air conditioner is located and send the data to the controller 7. The ambient temperature sensor 81 is located near the outdoor heat exchanger 2 or at the air inlet of the outdoor unit of the air conditioner, and can accurately reflect the outdoor ambient temperature. The coil temperature sensor 82 is electrically connected to the controller 7 and is used to detect the coil temperature of the outdoor heat exchanger 2 and send the data to the controller 7. The coil temperature sensor 82 is located on the coil of the outdoor heat exchanger 2 and can accurately reflect the condensation state of the refrigerant inside the outdoor heat exchanger 2.

[0065] The controller 7 determines whether the preset conditions are met based on the outdoor ambient temperature detected by the ambient temperature sensor 81 and the coil temperature detected by the coil temperature sensor 82. When the preset conditions are met, the controller controls the bypass valve 6 to open.

[0066] In some embodiments, the preset conditions include: the air conditioner is operating in cooling mode, and the outdoor ambient temperature is detected to be below a first temperature threshold and / or the coil temperature of the outdoor heat exchanger 2 is detected to be below a second temperature threshold. That is, the controller 8 is configured to: control the bypass valve 6 to open when the air conditioner is operating in cooling mode and the outdoor ambient temperature is detected to be below the first temperature threshold and / or the coil temperature of the outdoor heat exchanger 2 is detected to be below the second temperature threshold.

[0067] The first and second temperature thresholds can be preset according to factors such as the air conditioner model, refrigerant type, and operating environment. For example, the first temperature threshold can be set to 10℃, and the second temperature threshold can be set to 3℃. When the outdoor ambient temperature is lower than 10℃ and / or the coil temperature is lower than 3℃, the controller 7 determines that the preset conditions are met and controls the bypass valve 6 to open.

[0068] The following describes the operation of an air conditioner using some examples: After the air conditioner is turned on, the controller 7 first determines the current operating mode of the air conditioner. If the air conditioner is operating in heating mode, the controller 7 controls the bypass valve 6 to be closed. At this time, the bypass valve 6 is closed, and the exhaust port of the compressor 1 is not connected to the bypass intake port 54. In the refrigerant circulation loop, the refrigerant flows through the compressor 1, the indoor heat exchanger 3, the throttling device 4, the outdoor heat exchanger 2 in sequence, and finally flows back to the compressor 1.

[0069] If the air conditioner is operating in cooling mode, the controller 7 acquires the outdoor ambient temperature Tp detected by the ambient temperature sensor 81 and the outdoor heat exchanger coil temperature Tc detected by the coil temperature sensor 82. The controller 7 determines whether the outdoor ambient temperature Tp is lower than the first temperature threshold T1 and / or whether the coil temperature Tc is lower than the second temperature threshold T2.

[0070] If the outdoor ambient temperature Tp is not lower than the first temperature threshold T1, and the coil temperature Tc is not lower than the second temperature threshold T2, it indicates that both the outdoor ambient temperature and the coil temperature are within the normal range and do not fall under low-temperature conditions. At this time, the controller 7 controls the bypass valve 6 to remain closed, and the air conditioner operates in normal cooling mode. In the refrigerant circulation loop, the refrigerant flows sequentially through the compressor 1, outdoor heat exchanger 2, liquid receiver 5, throttling device 4, and indoor heat exchanger 3, finally returning to the compressor 1. The refrigerant from the outdoor heat exchanger 2 enters the chamber 51 through the refrigerant inlet 52 of the liquid receiver 5. After buffering and separation in the chamber 51, the liquid refrigerant flows out through the refrigerant outlet 53, enters the throttling device 4 for throttling and pressure reduction, then enters the indoor heat exchanger 3 for evaporation and heat absorption, and finally returns to the compressor 1.

[0071] If the outdoor ambient temperature Tp is lower than the first temperature threshold T1, and / or the coil temperature Tc is lower than the second temperature threshold T2, it indicates that the current operating condition is low temperature. The refrigerant condensation temperature and pressure in the outdoor heat exchanger 2 are low, the pressure difference before and after the throttling device 4 is insufficient, and the cooling start-up may be difficult. At this time, the controller 7 controls the bypass valve 6 to open, and the bypass valve 6 switches from the closed state to the open state. Part of the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 1 discharge port flows to the outdoor heat exchanger 2 through the refrigerant pipeline, and the other part is directly introduced into the chamber 51 of the liquid receiver 5 through the bypass valve 6 and the bypass inlet 54.

[0072] High-temperature, high-pressure gaseous refrigerant enters the upper part of chamber 51 through bypass inlet 54, directly contacting the low-temperature liquid refrigerant accumulated in the lower part of chamber 51. Because bypass inlet 54 is located in the upper part of chamber 51, the high-temperature gas enters from the top and forms natural convection with the liquid refrigerant in the lower part, resulting in a large gas-liquid contact area and high heat exchange efficiency. The high-temperature gaseous refrigerant transfers sensible heat to the liquid refrigerant, causing the liquid refrigerant temperature to rise, and the saturation pressure to rise simultaneously. At the same time, the high-temperature gaseous refrigerant itself cools down, partially condensing into liquid and mixing with the existing liquid refrigerant. The overall increase in temperature and pressure of the refrigerant in chamber 51 directly increases the pressure at the inlet of the throttling device 4, thereby increasing the pressure difference before and after the throttling device 4, providing sufficient power for refrigerant circulation.

[0073] Once the pressure differential is established, the refrigerant circulation is sufficient, allowing the evaporator (i.e., indoor heat exchanger 3) to promptly absorb heat from the room. The compressor 1's suction pressure remains stable, preventing frequent triggering of low-pressure protection due to a continuous drop in suction pressure. The compressor 1 operates smoothly during startup, with a high startup success rate and a good user experience.

[0074] After bypass valve 6 opens, controller 7 continuously monitors the coil temperature Tc detected by coil temperature sensor 82. When the coil temperature Tc rises above the third temperature threshold T3, controller 7 controls bypass valve 6 to close. The third temperature threshold T3 is equal to the sum of the second temperature threshold T2 and the first temperature difference ΔT, i.e., T3 = T2 + ΔT, where the first temperature difference ΔT is greater than zero. For example, if the second temperature threshold T2 is 3℃ and the first temperature difference ΔT is 5℃, then the third temperature threshold T3 is 8℃. When the coil temperature Tc rises above 8℃, controller 7 controls bypass valve 6 to close.

[0075] The aforementioned third temperature threshold T3 is higher than the second temperature threshold T2, creating a temperature hysteresis (first temperature difference ΔT). When the coil temperature Tc rises from a low temperature to the second temperature threshold T2, the bypass valve 6 will not close immediately, but will remain open until the coil temperature Tc rises to the third temperature threshold T3. This hysteresis control mechanism avoids frequent opening and closing of the bypass valve 6 when the coil temperature Tc fluctuates around the second temperature threshold T2, improving the operational stability of the air conditioner. Simultaneously, when the coil temperature Tc has fully risen above the third temperature threshold T3, it indicates that the refrigerant circulation loop has entered normal operating condition. At this point, closing the bypass valve 6 allows the refrigerant circulation loop to maintain a sufficient pressure differential through its own circulation, preventing premature closure that could lead to insufficient pressure differential and startup failure.

[0076] When the air conditioner receives a mode switching command (such as switching from cooling mode to heating mode) or a shutdown command, the controller 7 first controls the bypass valve 6 to close before executing the mode switching or shutdown. This control method ensures that the bypass valve 6 remains closed during mode switching or shutdown, without affecting the air conditioner's normal cooling or heating functions. It also prevents the refrigerant circulation circuit pressure from deviating from the normal operating range due to abnormal conduction of the bypass valve 6, thus improving the safety of the air conditioner's operation. Simultaneously, ensuring the bypass valve 6 is closed before shutdown allows the air conditioner to start from a normal initial state upon the next startup, preventing abnormal startup when the bypass valve 6 is open, protecting the compressor 1, and extending its service life.

[0077] In heating mode, controller 7 controls the bypass valve 6 to close. In heating mode, the high-temperature, high-pressure refrigerant discharged from compressor 1 flows to the indoor heat exchanger 3 (which acts as a condenser at this time) via a four-way valve. If bypass valve 6 is open, it will connect compressor 1's discharge port to the receiver 5, increasing the pressure inside receiver 5 and causing the high-pressure side pressure of the refrigerant circulation loop to deviate from the normal operating range. Therefore, by controlling the bypass valve 6 to close in heating mode, the integrity and efficiency of the heating cycle are ensured, preventing the refrigerant circulation loop from deviating from normal operation due to excessive pressure.

[0078] The air conditioner disclosed in this application utilizes a liquid receiver 5 with a chamber 51 located between the outlet of the outdoor heat exchanger 2 and the inlet of the throttling device 4. A bypass inlet 54, connected to the exhaust port of the compressor 1, is added to the liquid receiver 5. In conjunction with a bypass valve 6 and a controller 7, the high-temperature, high-pressure refrigerant discharged from the compressor 1 is introduced into the liquid receiver 5 under low-temperature conditions. This refrigerant mixes with and is heated and pressurized within the liquid receiver 5, rapidly establishing a pressure difference across the throttling device 4 and solving the problem of difficult cooling startup under low-temperature conditions. This solution has a simple structure, requires no replacement of core components such as the compressor 1, outdoor heat exchanger 2, and indoor heat exchanger 3, and is low in cost and widely applicable.

[0079] The control method of the air conditioner in this application will be described below: The controller 7 is configured to execute the control method of the air conditioner. After the air conditioner is turned on, it first determines the current working mode of the air conditioner. If the air conditioner is working in the cooling mode, it further obtains the outdoor ambient temperature and / or the coil temperature of the outdoor heat exchanger. If the outdoor ambient temperature is below a first temperature threshold and / or the coil temperature of the outdoor heat exchanger is below a second temperature threshold, it controls the bypass valve to open so that the refrigerant discharged from the compressor's exhaust port is introduced into the receiver through the bypass valve and the bypass inlet.

[0080] Figure 3 A flowchart of a control method for an air conditioner according to an embodiment of this application is shown.

[0081] like Figure 3 As shown, the control method includes at least steps S310 to S370, which are described in detail below.

[0082] In step S310, the operating mode of the air conditioner is obtained.

[0083] The operating mode can be either cooling or heating, which can be determined by detecting the switching status of the four-way valve or by receiving the user's mode setting command.

[0084] In step S320, it is determined whether the air conditioner is working in cooling mode. If so, step S330 is executed.

[0085] In step S330, the cooling mode is entered, and the outdoor ambient temperature and the outdoor heat exchanger coil temperature are obtained.

[0086] The outdoor ambient temperature can be obtained by an ambient temperature sensor located near the outdoor heat exchanger or at the air inlet of the outdoor unit of the air conditioner. The outdoor heat exchanger coil temperature can be obtained by a coil temperature sensor located on the outdoor heat exchanger coil.

[0087] In step S340, it is determined whether the outdoor ambient temperature is less than the first temperature threshold and the outdoor heat exchanger coil temperature is less than the second temperature threshold. If so, step S350 is executed; otherwise, step S360 is executed.

[0088] In step S350, the bypass valve is opened. Then, proceed to step S370.

[0089] In step S350, the controller energizes and opens the bypass valve, switching it from a closed to an open state, connecting the compressor discharge port to the bypass inlet. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor is introduced into the receiver chamber via the bypass valve and bypass inlet, mixing with the refrigerant from the outdoor heat exchanger. The high-temperature, high-pressure gaseous refrigerant enters from the upper part of the chamber, directly contacting the low-temperature liquid refrigerant accumulated at the lower part, causing the liquid refrigerant to gain sensible heat, increasing its temperature and saturation pressure simultaneously. This increases the pressure difference across the throttling device, providing sufficient refrigerant circulation power and mass flow rate for the refrigerant circulation loop startup, thus improving the deficiency of frequent low-pressure protection during refrigeration startup under low-temperature conditions.

[0090] In step S370, it is determined whether the temperature of the outdoor heat exchanger coil is greater than the third temperature threshold. If so, step S360 is executed; otherwise, step S330 is returned to continue monitoring the coil temperature.

[0091] The third temperature threshold is greater than the second temperature threshold, and the third temperature threshold equals the sum of the second temperature threshold and the first temperature difference, forming a temperature hysteresis Δt. When the coil temperature rises from the low temperature to the second temperature threshold, the bypass valve will not close immediately, but will remain open until the coil temperature rises above the third temperature threshold. This hysteresis control mechanism can prevent the bypass valve from frequently opening and closing when the coil temperature fluctuates near the second temperature threshold, improving the stability of the air conditioner's operation. At the same time, when the coil temperature has fully risen above the third temperature threshold, it indicates that the refrigerant circulation loop has entered normal operating condition. At this time, closing the bypass valve allows the refrigerant circulation loop to maintain a sufficient pressure difference through its own circulation, avoiding premature closure that could lead to insufficient pressure difference and startup failure.

[0092] In step S360, the bypass valve is closed.

[0093] In step S360, the bypass valve is placed in an isolated state, preventing the compressor discharge port from connecting with the bypass inlet, thus preventing refrigerant from entering the receiver through the bypass valve. The air conditioner operates in normal cooling mode, with the refrigerant flowing sequentially through the compressor, outdoor heat exchanger, receiver, throttling device, and indoor heat exchanger in the refrigerant circulation loop, finally returning to the compressor. Refrigerant from the outdoor heat exchanger enters the receiver chamber through the refrigerant inlet. After buffering and separation within the chamber, the liquid refrigerant flows out through the refrigerant outlet, enters the throttling device for pressure reduction, then enters the indoor heat exchanger for evaporation and heat absorption, finally returning to the compressor.

[0094] Figure 3 In the illustrated embodiment, a liquid receiver with a chamber is connected in series between the outdoor heat exchanger and the throttling device. A bypass inlet connected to the compressor exhaust port is provided on the liquid receiver. When the air conditioner is operating in cooling mode, and the outdoor ambient temperature is detected to be below a first temperature threshold and the coil temperature of the outdoor heat exchanger is detected to be below a second temperature threshold, the bypass valve is opened. This allows the high-temperature, high-pressure refrigerant discharged from the compressor exhaust port to be introduced into the liquid receiver chamber through the bypass valve and the bypass inlet, mixing with the refrigerant from the outdoor heat exchanger within the chamber, thereby increasing the pressure of the refrigerant in the liquid receiver. Since the liquid receiver is connected in series in the refrigerant circulation loop and located before the inlet of the throttling device, the increase in refrigerant pressure in the liquid receiver increases the pressure difference before and after the throttling device. This provides sufficient refrigerant circulation power for compressor startup, effectively solving the problem of insufficient pressure difference caused by excessively low condensing pressure during cooling startup under low-temperature conditions. It also improves the defect of frequent low-pressure protection triggering during the cooling startup phase, enhancing the stability and reliability of cooling startup under low-temperature conditions.

[0095] In some embodiments, when the air conditioner is operating in heating mode, the bypass valve is closed to prevent the compressor's exhaust port from communicating with the bypass intake port.

[0096] Figure 4 A flowchart of a control method for an air conditioner according to another embodiment of this application is shown.

[0097] like Figure 4 As shown, the control method includes at least steps S410 to S480, which are described in detail below.

[0098] In step S410, the operating mode of the air conditioner is obtained.

[0099] The operating mode can be either cooling or heating, which can be determined by detecting the switching status of the four-way valve or by receiving the user's mode setting command.

[0100] In step S420, it is determined whether the air conditioner is working in cooling mode. If so, step S430 is executed; otherwise, step S480 is executed.

[0101] In step S430, the cooling mode is entered, and the outdoor ambient temperature and the outdoor heat exchanger coil temperature are obtained.

[0102] In step S440, it is determined whether the outdoor ambient temperature is less than the first temperature threshold and the outdoor heat exchanger coil temperature is less than the second temperature threshold. If so, step S450 is executed; otherwise, step S460 is executed.

[0103] In step S450, the bypass valve is opened. Then, proceed to step S470.

[0104] In step S470, it is determined whether the temperature of the outdoor heat exchanger coil is greater than the third temperature threshold. If so, step S460 is executed; otherwise, step S430 is returned to continue monitoring the coil temperature.

[0105] In step S460, the bypass valve is closed.

[0106] In step S480, the heating mode is entered and the bypass valve is closed.

[0107] In step S480, during heating mode, the high-temperature, high-pressure refrigerant discharged from the compressor outlet flows to the indoor heat exchanger (which acts as a condenser at this time) via a four-way valve. If the bypass valve opens, it will connect the compressor outlet to the receiver, causing the pressure inside the receiver to rise. This results in excessive pressure on the high-pressure side of the refrigerant circulation loop, deviating from the normal operating range. By controlling the bypass valve to close during heating mode, the integrity and efficiency of the heating cycle are ensured, preventing excessive pressure in the refrigerant circulation loop from deviating from normal operation.

[0108] In some embodiments, when a working mode switching command or a shutdown command is received, the bypass valve is closed, and then the working mode switching command or shutdown command is executed.

[0109] Figure 5 A flowchart of a control method for an air conditioner according to another embodiment of this application is shown.

[0110] like Figure 5 As shown, the control method includes at least steps S510 to S590, which are described in detail below.

[0111] In step S510, the operating mode of the air conditioner is obtained.

[0112] The operating mode can be either cooling or heating, which can be determined by detecting the switching status of the four-way valve or by receiving the user's mode setting command.

[0113] In step S520, it is determined whether the air conditioner is working in cooling mode. If so, step S530 is executed; otherwise, step S580 is executed.

[0114] In step S530, the cooling mode is entered, and the outdoor ambient temperature and the outdoor heat exchanger coil temperature are obtained.

[0115] In step S540, it is determined whether the outdoor ambient temperature is less than the first temperature threshold and the outdoor heat exchanger coil temperature is less than the second temperature threshold. If so, step S550 is executed; otherwise, step S560 is executed.

[0116] In step S550, the bypass valve is opened. Then, proceed to step S570.

[0117] In step S570, it is determined whether the temperature of the outdoor heat exchanger coil is greater than the third temperature threshold. If so, step S560 is executed; otherwise, step S530 is returned to continue monitoring the coil temperature.

[0118] In step S560, the bypass valve is closed.

[0119] In step S580, the heating mode is entered and the bypass valve is closed.

[0120] In step S590, when a power-off command or mode switching command is received, step S560 is executed; then, the power-off or mode switching is executed again.

[0121] In step S590, when the air conditioner receives a shutdown command or mode switching command, regardless of the bypass valve's state, the bypass valve is first switched to the closed state before the shutdown or mode switching is executed. This control method ensures that the bypass valve remains closed during shutdown or mode switching, without affecting the air conditioner's normal cooling or heating functions. It also prevents the refrigerant circulation circuit pressure from deviating from the normal operating range due to abnormal bypass valve conduction, thus improving the safety of air conditioner operation. Simultaneously, ensuring the bypass valve is closed before shutdown ensures the refrigerant circulation circuit starts from its normal initial state upon the next startup, preventing abnormal refrigerant circulation circuit conditions when the bypass valve is open, protecting the compressor and extending its service life. After completing the shutdown or mode switching, the process returns to step S510, awaiting the next startup for mode determination.

[0122] In the above embodiments, using the outdoor ambient temperature being lower than a first temperature threshold and the outdoor heat exchanger coil temperature being lower than a second temperature threshold as the trigger condition for controlling the bypass valve to open is only a part of the embodiments of this application. In other embodiments, the trigger condition for controlling the bypass valve to open may be solely the outdoor ambient temperature being lower than the first temperature threshold, or the trigger condition may be the outdoor heat exchanger coil temperature being lower than the second temperature threshold. Alternatively, other conditions may be further set to determine whether to control the bypass valve to open.

[0123] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of this application is limited only by the appended claims.

Claims

1. An air conditioner, characterized in that, include: The compressor, outdoor heat exchanger, indoor heat exchanger, and throttling device are connected in sequence to form a refrigerant circulation loop. A receiver is connected in series in the refrigerant circulation loop and located between the outdoor heat exchanger and the throttling device. The receiver has a chamber and a refrigerant inlet, a refrigerant outlet and a bypass inlet communicating with the chamber. The refrigerant inlet is connected to the outdoor heat exchanger and the refrigerant outlet is connected to the throttling device. The chamber is used to contain the refrigerant entering through the refrigerant inlet and the bypass inlet. A bypass valve, one end of which is connected to the exhaust port of the compressor, and the other end of which is connected to the bypass inlet of the liquid receiver. When the bypass valve is open, the exhaust port of the compressor is connected to the bypass inlet. The controller, electrically connected to the bypass valve, is used to control the bypass valve to open so that the refrigerant discharged from the compressor's exhaust port is introduced into the liquid receiver through the bypass valve and the bypass inlet, or to control the bypass valve to close.

2. The air conditioner according to claim 1, characterized in that, The liquid reservoir includes a liquid reservoir body having the chamber, and a refrigerant outlet pipe is provided on the liquid reservoir body. The refrigerant outlet pipe is connected to the throttling device and forms the refrigerant outlet. The refrigerant outlet pipe extends into the chamber, and the refrigerant outlet is located at the bottom of the chamber and has a gap between it and the bottom wall of the chamber.

3. The air conditioner according to claim 1, characterized in that, The refrigerant inlet is located at the top of the chamber; and / or, the bypass air inlet is located at the top of the chamber.

4. The air conditioner according to claim 1, characterized in that, The controller is configured to open the bypass valve when the air conditioner is operating in cooling mode and the outdoor ambient temperature where the air conditioner is located is detected to be below a first temperature threshold and / or the coil temperature of the outdoor heat exchanger is detected to be below a second temperature threshold.

5. The air conditioner according to any one of claims 1 to 4, characterized in that, Also includes: An ambient temperature sensor, electrically connected to the controller, is used to detect the outdoor ambient temperature where the air conditioner is located and send it to the controller; A coil temperature sensor, electrically connected to the controller, is used to detect the coil temperature of the outdoor heat exchanger and send it to the controller.

6. The air conditioner according to claim 1, characterized in that, The controller is configured to close the bypass valve when the air conditioner is operating in heating mode. When the bypass valve is closed, the compressor's exhaust port is not connected to the bypass intake port.

7. A control method for an air conditioner, characterized in that, The air conditioner is as described in any one of claims 1 to 6, and the control method includes: When the air conditioner is operating in cooling mode, the outdoor ambient temperature and / or the coil temperature of the outdoor heat exchanger are obtained. When the outdoor ambient temperature is below a first temperature threshold and / or the coil temperature of the outdoor heat exchanger is below a second temperature threshold, the bypass valve is controlled to open so that the refrigerant discharged from the compressor's exhaust port is introduced into the liquid receiver through the bypass valve and the bypass inlet.

8. The control method according to claim 7, characterized in that, Also includes: When the coil temperature of the outdoor heat exchanger reaches or exceeds the third temperature threshold, the bypass valve is controlled to close. Wherein, the third temperature threshold is equal to the sum of the second temperature threshold and the first temperature difference, and the first temperature difference is greater than zero.

9. The control method according to claim 7, characterized in that, Also includes: When the air conditioner is operating in heating mode, the bypass valve is closed to prevent the compressor's exhaust port from connecting with the bypass intake port.

10. The control method according to claim 7, characterized in that, Also includes: When a working mode switching command or a shutdown command is received, the bypass valve is controlled to close, and then the working mode switching command or the shutdown command is executed.

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