Air conditioner capable of efficiently defrosting and defrosting control method thereof

Abstract

According to the air conditioner capable of achieving efficient defrosting and the air conditioner defrosting control method, an outdoor heat exchanger is arranged and comprises a first refrigerant pipeline and a second refrigerant pipeline which are connected in parallel, and a throttling valve is arranged on the first refrigerant pipeline located on the upper portion; a first temperature detector and a second temperature detector are arranged outside a first refrigerant pipeline and a second refrigerant pipeline respectively, and when defrosting is executed, a first temperature value detected by the first temperature detector and a second temperature value detected by the second temperature detector are obtained; and the target opening degree of the throttling valve is adjusted based on the temperature difference value between the first temperature value and the second temperature value. The temperature difference value between the first temperature value and the second temperature value can reflect the difference between the frost layer degrees of the upper portion and the lower portion of the outdoor heat exchanger, so that the refrigerant flow of the upper portion and the lower portion of the outdoor heat exchanger can be matched with the defrosting process by adjusting defrosting refrigerant flow distribution, and the refrigerant utilization efficiency is improved. Therefore, defrosting efficiency of the outdoor heat exchanger is improved, and energy is saved.

Description

Technical Field

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

[0002] In winter or cold environments, when an air conditioner is operating in heating mode, the surface temperature of the outdoor heat exchanger (functionally equivalent to the evaporator in the refrigeration cycle) is often below the freezing point (0°C). This causes water vapor in the ambient air to undergo a phase change and condense on its surface, forming a frost layer. This frost layer adheres to the fin structure of the outdoor heat exchanger, hindering airflow, reducing heat exchange efficiency, and ultimately leading to a decrease in the air conditioner's heating capacity and an increase in energy consumption.

[0003] In related technologies, to prevent frost from affecting the heating capacity of air conditioners, when the air conditioner is operating in heating mode and reaches the defrosting conditions, the four-way valve is switched to change the refrigerant flow direction, transforming the outdoor heat exchanger, which was originally an evaporator, into a condenser. The high-temperature, high-pressure gas discharged from the compressor is used to heat the condenser, thus melting the frost. During defrosting, the frost at the bottom of the outdoor heat exchanger melts more slowly than the frost at the top. When the frost at the top of the outdoor heat exchanger has already melted, the entire defrosting cycle needs to be extended to melt the frost at the bottom. This results in low defrosting efficiency for the outdoor heat exchanger and easily leads to energy waste.

[0004] Therefore, it is necessary to optimize the structural design and defrosting strategy of air conditioners. Summary of the Invention

[0005] To address the aforementioned problems, this application provides an air conditioner capable of efficient defrosting, comprising a refrigerant circulation loop, a throttling valve, a first temperature detector, a second temperature detector, and a controller. The refrigerant circulation loop allows refrigerant to circulate within a loop consisting of a compressor, condenser, throttling device, and evaporator. One of the condenser and evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger. The outdoor heat exchanger includes a first refrigerant pipe and a second refrigerant pipe connected in parallel, which are used to connect the compressor and the indoor heat exchanger. The first refrigerant pipe is located above the second refrigerant pipe. The throttling valve is located on the first refrigerant pipe to adjust the refrigerant flow rate. The first temperature detector is located outside the first refrigerant pipe to detect the temperature outside the first refrigerant pipe. The second temperature detector is located outside the second refrigerant pipe to detect the temperature outside the second refrigerant pipe, and the second temperature detector is located below the midline of the outdoor heat exchanger's height.

[0006] The controller is electrically connected to a first temperature detector, a second temperature detector, and a throttle valve, and is configured to execute a defrosting strategy. The defrosting strategy includes: when defrosting is performed, acquiring a first temperature value detected by the first temperature detector and a second temperature value detected by the second temperature detector; calculating the temperature difference between the first temperature value and the second temperature value, and adjusting the opening of the throttle valve based on the temperature difference, wherein the larger the temperature difference, the smaller the opening of the throttle valve; and exiting defrosting when the second temperature value detected by the second temperature detector reaches or exceeds a temperature threshold.

[0007] Thus, in the above technical solution, the outdoor heat exchanger includes a first refrigerant pipeline and a second refrigerant pipeline connected in parallel. A throttling valve is installed on the upper first refrigerant pipeline. A first temperature detector and a second temperature detector are respectively installed outside the first and second refrigerant pipelines. When defrosting is performed, the first temperature value detected by the first temperature detector and the second temperature value detected by the second temperature detector are acquired. Based on the temperature difference between the first and second temperature values, the target opening of the throttling valve is adjusted, thereby adjusting the refrigerant flow distribution of the first and second refrigerant pipelines. This achieves the adjustment of the defrosting refrigerant flow distribution between the upper and lower parts of the outdoor heat exchanger. The temperature difference between the first and second temperature values ​​reflects the difference in the degree of frost layer between the upper and lower parts of the outdoor heat exchanger. Adjusting the defrosting refrigerant flow distribution accordingly allows the refrigerant flow in the upper and lower parts of the outdoor heat exchanger to match the defrosting process, improving refrigerant utilization efficiency, thereby improving the defrosting efficiency of the outdoor heat exchanger and saving energy.

[0008] In some embodiments of this application, adjusting the opening of the throttle valve based on the temperature difference includes: obtaining the target opening of the throttle valve based on the temperature difference, wherein the larger the temperature difference, the smaller the target opening of the throttle valve; if the target opening reaches or exceeds a first opening, then adjusting the opening of the throttle valve to the target opening; otherwise, adjusting the opening of the throttle valve to the first opening.

[0009] In the above technical solution, before adjusting the opening of the throttle valve, it is first determined whether the target opening of the throttle valve has reached or exceeded the first opening. When the target opening reaches or exceeds the first opening, the opening of the throttle valve is then adjusted to the target opening. Otherwise, the opening of the throttle valve is adjusted to the first opening. This can prevent the system pressure from exceeding the safety threshold due to the throttle valve opening being too small, thus ensuring the normal operation of the compressor and protecting the compressor and refrigerant pipeline.

[0010] In some embodiments of this application, obtaining the target opening degree of the throttle valve based on the temperature difference includes: querying a mapping table based on the temperature difference to obtain the target opening degree of the throttle valve; wherein the mapping table contains the mapping relationship between the temperature difference and the target opening degree.

[0011] In the above technical solution, the target opening degree of the throttle valve is obtained by querying the mapping relationship table based on the temperature difference, which makes the acquisition of the target opening degree of the throttle valve simple.

[0012] In some embodiments of this application, the defrosting strategy includes: after adjusting the opening of the throttle valve based on the temperature difference, running the throttle valve at the adjusted opening for a first duration; and after running the throttle valve at the adjusted opening for a first duration, performing a step of determining whether the second temperature value detected by the second temperature detector reaches or exceeds a temperature threshold.

[0013] In the above technical solution, after adjusting the opening of the throttle valve based on the temperature difference, the system first maintains the adjusted throttle valve opening for a first duration, and then executes the step of judging whether the second temperature value detected by the second temperature detector has reached or exceeded the temperature threshold. This achieves the acquisition of temperature data in a relatively stable state, ensuring the accuracy of the first and second temperature values, while avoiding the mis-execution of the defrosting exit strategy and the excessively frequent adjustment of the throttle valve opening.

[0014] In some embodiments of this application, when the second temperature value detected by the second temperature detector reaches or exceeds a temperature threshold, defrosting is terminated, including: when the second temperature value detected by the second temperature detector reaches or exceeds a temperature threshold, obtaining the duration for which the second temperature value reaches or exceeds the temperature threshold; if the duration for which the second temperature value reaches or exceeds the temperature threshold reaches or exceeds a second duration, then defrosting is terminated.

[0015] In the above technical solution, if the second temperature value detected by the second temperature detector reaches or exceeds the temperature threshold, the duration for which the second temperature value reaches or exceeds the temperature threshold is further obtained. Defrosting is only stopped when the duration for which the second temperature value reaches or exceeds the temperature threshold reaches or exceeds the second duration. This can avoid the situation where defrosting is mistakenly stopped due to instantaneous temperature fluctuations before the external temperature of the second refrigerant pipeline has stabilized and reached or exceeded the temperature threshold, thus affecting the defrosting effect of the outdoor heat exchanger.

[0016] In some embodiments of this application, the defrosting strategy includes: determining a temperature threshold based on the outdoor ambient temperature where the air conditioner is located, wherein the temperature threshold is positively correlated with the outdoor ambient temperature.

[0017] In the above technical solution, the temperature threshold is positively correlated with the outdoor ambient temperature. When the outdoor ambient temperature where the air conditioner is located is low, setting a smaller temperature threshold can avoid excessively long defrosting time and heat waste in cold weather, while shortening the time of interruption of heating during defrosting to ensure heating demand. When the outdoor ambient temperature where the air conditioner is located is high, setting a higher temperature threshold can extend the effective heating time between two defrosting cycles in hot weather and avoid frequent defrosting starts.

[0018] In some embodiments of this application, the defrosting strategy includes: obtaining the continuous operating time of the compressor during defrosting; and when the operating time reaches a third duration or more, performing the step of obtaining a first temperature value detected by a first temperature detector and a second temperature value detected by a second temperature detector.

[0019] In the above technical solution, when the compressor runs continuously for more than three hours during defrosting, the first temperature value detected by the first temperature detector and the second temperature value detected by the second temperature detector are obtained, and the temperature difference and throttle valve opening adjustment steps are further executed, which can reduce unnecessary processing logic.

[0020] In some embodiments of this application, the air conditioner includes a four-way valve. The first port of the four-way valve is connected to the compressor's exhaust port, the second port is connected to the indoor heat exchanger, the third port is connected to the outdoor heat exchanger, a throttling device is provided between the outdoor and indoor heat exchangers, and the fourth port is connected to the compressor's intake port. The defrosting strategy includes controlling the four-way valve to switch the refrigerant flow direction so that it flows out from the compressor's exhaust port, sequentially through the first port of the four-way valve, the third port of the four-way valve, the outdoor heat exchanger, the throttling device, the indoor heat exchanger, the second port of the four-way valve, and the fourth port of the four-way valve, before returning to the compressor through the compressor's intake port to perform defrosting.

[0021] In the above technical solution, the refrigerant flow direction is switched by a four-way valve, which avoids the need for frequent compressor start-stop or other complex operations to achieve mode switching and defrosting functions, and reduces the probability of wear and failure of key components such as compressors.

[0022] In some embodiments of this application, the periphery of the first refrigerant pipe and the second refrigerant pipe is provided with fins, and the surface of the fins is coated with a hydrophobic coating.

[0023] In the above technical solution, the fin surface of the outdoor heat exchanger is coated with a hydrophobic coating, which can suppress the frosting rate on the surface of the outdoor heat exchanger, thereby reducing the defrosting frequency of the outdoor heat exchanger. At the same time, the frost layer at the bottom of the outdoor heat exchanger is melted faster by adjusting the opening of the throttle valve, so as to prevent the frost layer falling from the top of the outdoor heat exchanger from accumulating at the bottom of the outdoor heat exchanger and ensuring the defrosting effect of the outdoor heat exchanger.

[0024] This application also provides a defrosting control method for an air conditioner, as described above. The defrosting control method includes: acquiring a first temperature value detected by a first temperature detector and a second temperature value detected by a second temperature detector; calculating the temperature difference between the first temperature value and the second temperature value, and adjusting the opening of a throttle valve based on the temperature difference, wherein the larger the temperature difference, the smaller the opening of the throttle valve; determining whether the second temperature value reaches or exceeds a temperature threshold, and when the second temperature value reaches or exceeds the temperature threshold, exiting defrosting.

[0025] The above technical solution improves the overall defrosting efficiency of the outdoor heat exchanger and saves energy by optimizing the defrosting method of the air conditioner.

[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 structure of an air conditioner according to an embodiment of this application is shown.

[0029] Figure 2 A partial structural schematic diagram of an outdoor heat exchanger according to an embodiment of this application is shown.

[0030] Figure 3 A schematic diagram showing the installation orientation of a temperature detector according to an embodiment of this application is provided.

[0031] Figure 4 A block diagram of an air conditioner electronic control system according to an embodiment of this application is shown.

[0032] Figure 5 A flowchart illustrating a defrosting strategy according to an embodiment of this application is shown.

[0033] Figure 6 A detailed flowchart of the steps for adjusting the throttle valve opening according to an embodiment of this application is shown.

[0034] Figure 7 A detailed flowchart of the second temperature value determination step according to an embodiment of this application is shown.

[0035] Figure 8 A flowchart illustrating another embodiment of the defrosting strategy of this application is shown.

[0036] Figure 9 A flowchart illustrating a defrosting strategy according to yet another embodiment of this application is shown.

[0037] The annotations in the attached figures are explained as follows: 11. Indoor heat exchanger; 12. Indoor fan; 21. Compressor; 22. Four-way valve; 23. Outdoor heat exchanger; 231. First refrigerant line; 232. Second refrigerant line; 233. First refrigerant interface; 234. Second refrigerant interface; 24. Outdoor fan; 25. Throttling valve; 261. First temperature detector; 262. Second temperature detector; 27. Controller; 28. Throttling device. Detailed Implementation

[0038] 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.

[0039] 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.

[0040] In the description of this application, it should be understood that the terms "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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, and therefore should not be construed as a limitation of this application.

[0041] 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.

[0042] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" 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.

[0043] 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.

[0044] In related technologies, air conditioners suffer from low defrosting efficiency of the outdoor heat exchanger. This is because cold air, being denser, naturally sinks. The frost layer at the bottom of the outdoor heat exchanger is typically the thickest and densest. Simultaneously, this lower area is often the end of the refrigerant flow, resulting in a relatively insufficient supply of heat and refrigerant during defrosting, creating a "hot at the top, cold at the bottom" situation. While the frost layer in the upper, thinner areas has melted quickly, the thickest frost layer at the bottom remains in a slow melting state. To wait for the bottom frost layer to be completely removed, the entire defrosting cycle must be extended. This is especially true for outdoor heat exchangers with hydrophobic coatings on the fins. The surface characteristics of these coatings cause frost to detach in solid form before it is fully melted during defrosting, accumulating at the bottom of the outdoor heat exchanger. This results in more heat being required for defrosting at the bottom of the outdoor heat exchanger, a longer defrosting time, and ultimately a longer overall defrosting cycle for the outdoor heat exchanger.

[0045] In view of this, this application sets up an outdoor heat exchanger including a first refrigerant pipeline and a second refrigerant pipeline connected in parallel. A throttling valve is installed on the upper first refrigerant pipeline. A first temperature detector and a second temperature detector are respectively installed outside the first and second refrigerant pipelines. When defrosting is performed, the first temperature value detected by the first temperature detector and the second temperature value detected by the second temperature detector are acquired. The opening of the throttling valve is adjusted based on the temperature difference between the first and second temperature values, thereby adjusting the refrigerant flow distribution of the first and second refrigerant pipelines, and realizing the adjustment of the defrosting refrigerant flow distribution between the upper and lower parts of the outdoor heat exchanger. The temperature difference between the first and second temperature values ​​can reflect the difference in the degree of frost layer between the upper and lower parts of the outdoor heat exchanger. Adjusting the defrosting refrigerant flow distribution accordingly can adapt the refrigerant flow in the upper and lower parts of the outdoor heat exchanger to the defrosting process, improve refrigerant utilization efficiency, and thus improve the defrosting efficiency of the outdoor heat exchanger and save energy.

[0046] 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.

[0047] Figure 1 A schematic diagram of the structure of an air conditioner according to an embodiment of this application is shown. Figure 2 A partial structural schematic diagram of an outdoor heat exchanger according to an embodiment of this application is shown.

[0048] An air conditioner has a refrigerant circulation loop, which circulates the refrigerant through a circuit consisting of a compressor, condenser, expansion device, and evaporator, thus performing a cooling / heating cycle. The cooling / heating cycle involves a series of processes including compression, condensation, expansion, and evaporation. The compressor compresses the refrigerant gas at high temperature and pressure and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser, where it condenses the compressed refrigerant into a liquid phase, releasing heat to the surrounding environment through the condensation process. The expansion device causes the high-temperature, high-pressure liquid refrigerant condensed in the condenser to expand into a low-pressure liquid refrigerant phase. The evaporator evaporates the refrigerant that expanded in the expansion device and returns the low-temperature, low-pressure refrigerant gas to the compressor. The evaporator achieves a cooling effect by utilizing the latent heat of refrigerant evaporation to exchange heat with the material being cooled. Throughout the cooling / heating cycle, the air conditioner regulates the temperature of the indoor space.

[0049] The air conditioner described in this application has 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 through the indoor heat exchanger, then, after being depressurized by the throttling device, enters the outdoor heat exchanger, and finally returns to the compressor through the four-way valve to complete the heating cycle. In this mode, the indoor heat exchanger functions as an evaporator, and the indoor heat exchanger functions as a condenser.

[0050] The air conditioner in this embodiment includes an indoor unit and an outdoor unit. The indoor unit is used to regulate the temperature of the indoor space; in cooling mode, it lowers the temperature of the indoor space; in heating mode, it raises the temperature of the indoor space.

[0051] The indoor unit includes an indoor unit housing (not shown in the figure), which has a receiving chamber for accommodating the components of the indoor unit.

[0052] like Figure 1 As shown, the indoor unit also includes an indoor heat exchanger 11 and an indoor fan 12. The indoor heat exchanger 11 and the indoor fan 12 are arranged in the housing cavity of the indoor unit casing. The indoor fan 12 and the indoor heat exchanger 11 are arranged opposite to each other. After the air is heated by the indoor heat exchanger 11, it is blown into the indoor space by the action of the indoor fan 12, thereby regulating the temperature of the indoor space.

[0053] The outdoor unit includes an outdoor unit housing (not shown in the figure), which has a receiving chamber for housing the components of the outdoor unit.

[0054] like Figure 1As shown, the outdoor unit also includes a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, and an outdoor fan 24. The compressor 21, the four-way valve 22, the outdoor heat exchanger 23, and the outdoor fan 24 are all located in the receiving cavity of the outdoor unit casing structure.

[0055] The compressor 21 is used to compress the refrigerant. The first port of the four-way valve 22 is connected to the exhaust port of the compressor 21, the second port of the four-way valve 22 is connected to the indoor heat exchanger 11, the third port of the four-way valve 22 is connected to the outdoor heat exchanger 23, a throttling device 28 is installed between the indoor heat exchanger 11 and the outdoor heat exchanger 23, and the fourth port of the four-way valve 22 is connected to the intake port of the compressor 21. By controlling the four-way valve 22, the flow direction of the refrigerant can be switched.

[0056] In cooling mode, the refrigerant is compressed by compressor 21 and flows out from the exhaust port of compressor 21. It then flows sequentially through four-way valve 22, outdoor heat exchanger 23, throttling device 28, and indoor heat exchanger 11, finally returning to the intake port of compressor 21 through four-way valve 22, completing the cooling cycle. In heating mode, the refrigerant is compressed by compressor 21 and flows out from the exhaust port of compressor 21. It then flows sequentially through four-way valve 22, indoor heat exchanger 11, throttling device 28, and outdoor heat exchanger 23, finally returning to the intake port of compressor 21 through four-way valve 22, completing the heating cycle.

[0057] In some embodiments, the throttling device 28 may be a capillary tube. In some embodiments, the throttling device 28 may be an expansion valve.

[0058] In some embodiments, the outdoor heat exchanger 23 is a vertical heat exchanger. The outdoor heat exchanger 23 is mounted on the chassis of the outdoor unit housing.

[0059] In some embodiments, such as Figure 2 As shown, the outdoor heat exchanger 23 includes a first refrigerant pipe 231 and a second refrigerant pipe 232 connected in parallel. The first refrigerant pipe 231 is located above the second refrigerant pipe 232; that is, the first refrigerant pipe 231 serves as the upper pipe of the outdoor heat exchanger 23, and the second refrigerant pipe 232 serves as the lower pipe of the outdoor heat exchanger 23. The first refrigerant pipe 231 and the second refrigerant pipe 232 are used to connect the compressor 21 and the indoor heat exchanger 11.

[0060] by Figure 1Taking the illustrated embodiment as an example, one end of the first refrigerant line 231 and the second refrigerant line 232 is connected to the third port of the four-way valve 22 and connected to the compressor 21 through the four-way valve 22. The other end of the first refrigerant line 231 and the second refrigerant line 232 is connected to the throttling device 28 and connected to the indoor heat exchanger 11 through the throttling device 28. During defrosting, refrigerant flows out from the exhaust port of compressor 21, sequentially passing through the first port of four-way valve 22, the third port of four-way valve 22, the first refrigerant line 231 and the second refrigerant line 232, the throttling device 28, the indoor heat exchanger 11, the second port of four-way valve 22, and the fourth port of four-way valve 22, before returning to compressor 21 through the intake port. During this process, the refrigerant flowing out from the third port of four-way valve 22 splits into two paths, entering the first refrigerant line 231 and the second refrigerant line 232 respectively through the first refrigerant port 233 of the outdoor heat exchanger 23. After flowing out from the first refrigerant line 231 and the second refrigerant line 232, it converges at the second refrigerant port 234 of the outdoor heat exchanger 23 and flows into the throttling device 28. Therefore, the refrigerant flow rate of the first refrigerant line 231 and the second refrigerant line 232 can be flexibly allocated.

[0061] In some embodiments, the first refrigerant line 231 is equipped with a throttle valve 25, which is used to adjust the refrigerant flow rate in the first refrigerant line 231. The refrigerant flow rate in the first refrigerant line 231 is positively correlated with the opening degree of the throttle valve 25. When the total refrigerant flow rate remains constant, when the opening degree of the throttle valve 25 increases, the refrigerant flow rate entering the first refrigerant line 231 increases, which in turn leads to a decrease in the refrigerant flow rate entering the second refrigerant line 232; conversely, when the opening degree of the throttle valve 25 decreases, the refrigerant flow rate entering the first refrigerant line 231 decreases, which in turn leads to an increase in the refrigerant flow rate entering the second refrigerant line 232. By adjusting the opening degree of the throttle valve 25, the refrigerant flow rate distribution between the first refrigerant line 231 and the second refrigerant line 232 can be adjusted.

[0062] In some embodiments, the periphery of the first refrigerant line 231 and the second refrigerant line 232 is provided with fins (not shown in the figure), and the surface of the fins is coated with a hydrophobic coating.

[0063] A hydrophobic coating is applied to the fin surface of the outdoor heat exchanger 23. The hydrophobic coating can suppress the frosting rate on the surface of the outdoor heat exchanger 23, thereby reducing the defrosting frequency of the outdoor heat exchanger 23.

[0064] In some embodiments, the outdoor fan 24 is arranged opposite to the outdoor heat exchanger 23. In cooling mode, the outdoor fan 24 causes air to flow through the fins of the outdoor heat exchanger 23, carrying away the heat from the outdoor heat exchanger 23 and helping the refrigerant dissipate heat; in heating mode, the outdoor fan 24 draws in cold air from the outside, which is heated as it passes through the outdoor heat exchanger 23, while also helping the refrigerant absorb heat.

[0065] In some embodiments, the outdoor fan 24 is an axial flow fan, with its blades parallel to the motor axis, allowing airflow to enter and exit axially. The motor drives the fan blades to rotate, providing axial thrust to the air and thus enabling air transport.

[0066] Figure 3 A schematic diagram showing the installation orientation of a temperature detector according to an embodiment of this application is provided.

[0067] like Figure 3 As shown, the outdoor unit also includes a first temperature detector 261 and a second temperature detector 262. The first temperature detector 261 and the second temperature detector 262 are set at different height positions of the outdoor heat exchanger 23 to detect the temperature at their respective height positions.

[0068] In some embodiments, a first temperature detector 261 is disposed outside the first refrigerant pipe 231 to detect the temperature outside the first refrigerant pipe 231, and a second temperature detector 262 is disposed outside the second refrigerant pipe 232 to detect the temperature outside the second refrigerant pipe 232. Furthermore, the second temperature detector 262 is located below the midline of the height of the outdoor heat exchanger 23. That is, if the first temperature detector 261 is disposed at the upper-middle position of the outdoor heat exchanger 23, the temperature outside the first refrigerant pipe 231 is the temperature of the upper-middle part of the outdoor heat exchanger 23; and if the second temperature detector 262 is disposed at the lower position of the outdoor heat exchanger 23, the temperature outside the second refrigerant pipe 232 is the temperature of the lower part of the outdoor heat exchanger 23.

[0069] The first temperature detector 261 may include one temperature sensor or multiple temperature sensors. When the first temperature detector 261 includes multiple temperature sensors, the multiple temperature sensors may be evenly arranged outside the first refrigerant pipe 231. When the first temperature detector 261 includes multiple temperature sensors, the average value of the temperature data detected by the multiple temperature sensors may be used as the temperature outside the first refrigerant pipe 231, or the median value of the temperature data detected by the multiple temperature sensors may be used as the temperature outside the first refrigerant pipe 231.

[0070] The second temperature detector 262 may include one temperature sensor or multiple temperature sensors. When the second temperature detector 262 includes multiple temperature sensors, the multiple temperature sensors may be evenly arranged outside the second refrigerant pipe 232. When the second temperature detector 262 includes multiple temperature sensors, the average value of the temperature data detected by the multiple temperature sensors may be used as the temperature outside the second refrigerant pipe 232, or the median value of the temperature data detected by the multiple temperature sensors may be used as the temperature outside the second refrigerant pipe 232.

[0071] Figure 4 A block diagram of an air conditioner electronic control system according to an embodiment of this application is shown.

[0072] The outdoor unit also includes a controller 27. For example... Figure 4 As shown, controller 27 can be electrically connected to compressor 21, and can send control signals to compressor 21 to control compressor 21 to start or stop, thereby maintaining the indoor temperature at the target temperature through the start and stop of compressor 21. Controller 27 can be electrically connected to each temperature sensor, and can receive temperature signals input from each sensor, controlling corresponding components based on these signals. Controller 27 can be electrically connected to outdoor fan 24, and can send control signals to outdoor fan 24 to control its start and stop. Controller 27 can be electrically connected to throttle valve 25, and can send control signals to throttle valve 25 to control its opening. Controller 27 can also be connected to other electrical control devices in the outdoor unit of the air conditioner, such as four-way valve 22, and can send control signals to four-way valve 22 to control the switching of refrigerant flow, thereby realizing a series of control processes for the air conditioner.

[0073] Controller 27 is configured to execute a defrosting strategy, such as Figure 5 As shown, the defrosting strategy includes at least steps S510 to S540, which are described in detail below.

[0074] In step S510, when defrosting is performed, the first temperature value detected by the first temperature detector and the second temperature value detected by the second temperature detector are obtained.

[0075] In step S520, the temperature difference between the first temperature value and the second temperature value is calculated.

[0076] The temperature difference between the first and second temperature values ​​can be calculated by subtracting the second temperature value from the first temperature value, or by subtracting the first temperature value from the second temperature value. The temperature difference is the numerical part obtained by subtracting the first and second temperature values.

[0077] In step S530, the opening of the throttle valve is adjusted based on the temperature difference, and the opening of the throttle valve is negatively correlated with the temperature difference.

[0078] That is, the greater the temperature difference between the first temperature value and the second temperature value, the smaller the opening of the throttle valve; conversely, the smaller the temperature difference between the first temperature value and the second temperature value, the larger the opening of the throttle valve.

[0079] The greater the temperature difference between the first and second temperature values, the greater the difference in defrosting degree between the first and second refrigerant lines. By reducing the opening of the throttle valve, the refrigerant flow rate entering the first refrigerant line is reduced. At the same time, the refrigerant flow rate entering the second refrigerant line will increase. This fully utilizes the heat of the refrigerant flow to accelerate the defrosting speed outside the second refrigerant line, making the refrigerant flow rates of the first and second refrigerant lines match the defrosting process. In other words, the refrigerant flow rates at the top and bottom of the outdoor heat exchanger match the defrosting process, improving refrigerant utilization efficiency, thereby improving the defrosting efficiency of the outdoor heat exchanger and saving energy.

[0080] In step S540, it is determined whether the second temperature value detected by the second temperature detector reaches or exceeds the temperature threshold. If so, defrosting is exited; otherwise, the process returns to step S510.

[0081] The temperature threshold can be a fixed temperature value set based on experience, or it can be a function value related to the outdoor ambient temperature where the outdoor unit of the air conditioner is located.

[0082] In some embodiments, a temperature threshold is determined based on the outdoor ambient temperature where the outdoor unit of the air conditioner is located, and the temperature threshold is positively correlated with the outdoor ambient temperature.

[0083] In other words, the higher the outdoor ambient temperature where the air conditioner outdoor unit is located, the larger the temperature threshold; conversely, the lower the outdoor ambient temperature where the air conditioner outdoor unit is located, the smaller the temperature threshold.

[0084] When the outdoor ambient temperature where the air conditioner outdoor unit is located is low, setting a lower temperature threshold can prevent excessively long defrosting time and heat waste in cold weather, while also shortening the time when heating is interrupted during defrosting to ensure heating needs are met. When the outdoor ambient temperature where the air conditioner outdoor unit is located is high, setting a higher temperature threshold can extend the effective heating time between two defrosting cycles in hot weather, avoiding frequent defrosting starts.

[0085] When the second temperature value detected by the second temperature detector reaches the temperature threshold, it indicates that the lower part of the outdoor heat exchanger has been basically defrosted, that is, the entire outdoor heat exchanger has been basically defrosted, so the defrosting can be stopped; if the second temperature value detected by the second temperature detector does not reach the temperature threshold, it indicates that the lower part of the outdoor heat exchanger has not been defrosted, so it is necessary to return to step S510 to cycle through the above steps S510 to S540 to ensure the defrosting effect of the outdoor heat exchanger.

[0086] exist Figure 5In the illustrated embodiment, a first temperature value detected by a first temperature detector and a second temperature value detected by a second temperature detector are obtained, and the temperature difference between the first and second temperature values ​​is calculated. The temperature difference between the first and second temperature values ​​reflects the difference in the degree of frost layer on the upper and lower parts of the outdoor heat exchanger. Based on this, the opening of the throttle valve is adjusted so that the refrigerant flow rate on the upper and lower parts of the outdoor heat exchanger is adapted to the defrosting process, thereby improving the refrigerant utilization efficiency, thus improving the defrosting efficiency of the outdoor heat exchanger and saving energy.

[0087] In some embodiments, to prevent the throttle valve opening from being too small, which could cause the system pressure to exceed the safety threshold, resulting in compressor overpressure protection shutdown, or even compressor damage and refrigerant pipeline rupture, the opening of the throttle valve should be adjusted before adjusting it. First, it should be determined whether the target opening of the throttle valve is above the safe opening.

[0088] In some embodiments, such as Figure 6 As shown, adjusting the opening of the throttle valve based on the temperature difference includes at least steps S610 to S640, which are described in detail below.

[0089] In step S610, the target opening degree of the throttle valve is obtained based on the temperature difference, and the target opening degree is negatively correlated with the temperature difference.

[0090] That is, the greater the temperature difference between the first temperature value and the second temperature value, the smaller the target opening of the throttle valve; conversely, the smaller the temperature difference between the first temperature value and the second temperature value, the larger the target opening of the throttle valve.

[0091] In some embodiments, the target opening degree of the throttle valve is obtained based on the temperature difference. This involves querying a mapping table based on the temperature difference to obtain the target opening degree of the throttle valve. Obtaining the target opening degree of the throttle valve by querying the mapping table based on the temperature difference is simple.

[0092] In some embodiments, the mapping relationship between temperature difference and target opening degree is shown in Table 1 below.

[0093] Table 1

[0094] That is, when the temperature difference is above 2℃ but below 3℃, the target opening of the throttle valve is 90% fully open; when the temperature difference is above 3℃ but below 4℃, the target opening of the throttle valve is 80% fully open; when the temperature difference is above 4℃ but below 5℃, the target opening of the throttle valve is 70% fully open; when the temperature difference is above 5℃ but below 6℃, the target opening of the throttle valve is 60% fully open; when the temperature difference is above 6℃ but below 7℃, the target opening of the throttle valve is 50% fully open; when the temperature difference is above 7℃ but below 8℃, the target opening of the throttle valve is 40% fully open; when the temperature difference is above 8℃ but below 10℃, the target opening of the throttle valve is 30% fully open; and when the temperature difference is above 10℃, the target opening of the throttle valve is 20% fully open.

[0095] Of course, in other embodiments, the target opening of the throttle valve can also be obtained in other ways, such as by constructing a functional relationship between the temperature difference and the target opening. When the temperature difference is calculated, the target opening of the throttle valve can be further calculated based on this functional relationship.

[0096] In step S620, it is determined whether the target opening degree has reached or exceeded the first opening degree. If so, step S630 is executed; otherwise, step S640 is executed.

[0097] The first opening is the minimum safe opening. When the opening of the throttle valve is less than this first opening, the system pressure may exceed the safe threshold.

[0098] In some embodiments, the first opening can be any value between 20% and 40% of the fully opened position. In step S630, the opening of the throttle valve is adjusted to the target opening.

[0099] In step S640, the opening degree of the throttle valve is adjusted to the first opening degree.

[0100] exist Figure 6 In the illustrated embodiment, before adjusting the opening of the throttle valve, it is first determined whether the target opening of the throttle valve has reached or exceeded the first opening. If the target opening has reached or exceeded the first opening, the opening of the throttle valve is then adjusted to the target opening. Otherwise, the opening of the throttle valve is adjusted to the first opening. This can prevent the system pressure from exceeding the safety threshold due to the throttle valve opening being too small, thus ensuring the normal operation of the compressor and protecting the compressor and refrigerant pipeline.

[0101] In some embodiments, the defrosting strategy includes: after adjusting the opening of the throttle valve based on the temperature difference, running the throttle valve at the adjusted opening for a first duration; and after running the throttle valve at the adjusted opening for the first duration, performing a step of determining whether the second temperature value detected by the second temperature detector reaches or exceeds a temperature threshold.

[0102] The duration can be a few seconds, such as 6 seconds.

[0103] When the opening of the throttle valve changes, the refrigerant flow distribution in the first and second refrigerant lines changes. During this process, the temperature values ​​detected by the first and second temperature detectors will fluctuate instantaneously. After adjusting the opening of the throttle valve based on the temperature difference, the system first maintains the adjusted throttle valve opening for a first duration, and then executes the step of judging whether the second temperature value detected by the second temperature detector has reached or exceeded the temperature threshold. This achieves temperature data collection in a relatively stable state, ensuring the accuracy of the first and second temperature values, while avoiding erroneous execution of the defrost exit strategy and excessively frequent adjustment of the throttle valve opening.

[0104] In some embodiments, if the second temperature value detected by the second temperature detector reaches or exceeds a temperature threshold, the duration for which the second temperature value has reached or exceeded the temperature threshold is further determined to avoid misjudgment of temperature due to temporary temperature fluctuations. Figure 7 As shown, the determination steps for whether the second temperature value has reached the temperature threshold include at least the following steps S710 to S730, which are described in detail below.

[0105] In step S710, it is determined whether the second temperature value detected by the second temperature detector reaches or exceeds the temperature threshold. If so, step S720 is executed.

[0106] In step S720, the duration for which the second temperature value reaches or exceeds the temperature threshold is obtained. Then, step S730 is executed.

[0107] In step S730, it is determined whether the duration for which the second temperature value reaches or exceeds the temperature threshold reaches or exceeds the second duration. If so, defrosting is exited; otherwise, the process returns to step S720.

[0108] The second duration can be a time value set based on experience.

[0109] exist Figure 7In the embodiment shown, if the second temperature value detected by the second temperature detector reaches or exceeds the temperature threshold, the duration for which the second temperature value reaches or exceeds the temperature threshold is further obtained. Defrosting is only terminated when the duration for which the second temperature value reaches or exceeds the temperature threshold reaches or exceeds the second duration. This avoids the possibility of erroneously terminating defrosting before the external temperature of the second refrigerant pipeline has stabilized and reached or exceeded the temperature threshold due to instantaneous temperature fluctuations, thus affecting the defrosting effect of the outdoor heat exchanger.

[0110] In some embodiments, the defrosting strategy further includes: obtaining the continuous operating time of the compressor during defrosting, and when the operating time reaches a third duration or more, then obtaining the first temperature value detected by the first temperature detector and the second temperature value detected by the second temperature detector.

[0111] like Figure 8 As shown, the defrosting strategy includes at least steps S810 to S890, which are described in detail below.

[0112] In step S810, the four-way valve is controlled to switch the refrigerant flow direction to the defrosting mode in order to perform defrosting.

[0113] In some embodiments, controlling the four-way valve to switch the refrigerant flow direction is as follows: the refrigerant flows out from the compressor's exhaust port, sequentially through the first port of the four-way valve, the third port of the four-way valve, the outdoor heat exchanger, the throttling device, the indoor heat exchanger, the second port of the four-way valve, and the fourth port of the four-way valve, and then flows back to the compressor through the compressor's intake port to perform defrosting.

[0114] In step S820, the runtime of the compressor during continuous operation when defrosting is obtained.

[0115] In step S830, it is determined whether the compressor's running time has reached the third duration or more. If so, step S840 is executed; otherwise, step S820 is returned.

[0116] The third duration can be a time value set based on experience.

[0117] In step S840, the first temperature value detected by the first temperature detector and the second temperature value detected by the second temperature detector are obtained.

[0118] In step S850, the temperature difference between the first temperature value and the second temperature value is calculated.

[0119] In step S860, the opening of the throttle valve is adjusted based on the temperature difference and maintained for a first duration.

[0120] Among them, the opening degree of the throttle valve is negatively correlated with the temperature difference.

[0121] In step S870, it is determined whether the second temperature value detected by the second temperature detector reaches or exceeds the temperature threshold. If so, step S880 is executed; otherwise, step S840 is returned.

[0122] In step S880, the duration for which the second temperature value reaches or exceeds the temperature threshold is obtained.

[0123] In step S890, it is determined whether the duration for which the second temperature value reaches or exceeds the temperature threshold reaches or exceeds the second duration. If so, defrosting is exited; otherwise, the process returns to step S880.

[0124] exist Figure 8 In the embodiment shown, when the compressor has been running continuously for more than three hours during defrosting, the first temperature value detected by the first temperature detector and the second temperature value detected by the second temperature detector are obtained, and the temperature difference and throttle valve opening adjustment steps are further executed, which can reduce unnecessary processing logic.

[0125] Figure 9 A flowchart illustrating a defrosting strategy according to yet another embodiment of this application is shown.

[0126] like Figure 9 As shown, the defrosting strategy includes at least steps S910 to S9120, which are described in detail below.

[0127] In step S910, the four-way valve is controlled to switch the refrigerant flow direction to the defrosting mode in order to perform defrosting.

[0128] In some embodiments, controlling the four-way valve to switch the refrigerant flow direction is as follows: the refrigerant flows out from the compressor's exhaust port, sequentially through the first port of the four-way valve, the third port of the four-way valve, the outdoor heat exchanger, the throttling device, the indoor heat exchanger, the second port of the four-way valve, and the fourth port of the four-way valve, and then flows back to the compressor through the compressor's intake port to perform defrosting.

[0129] In step S920, the runtime of the compressor during continuous operation when defrosting is obtained.

[0130] In step S930, it is determined whether the compressor's running time has reached the third duration or more. If so, step S940 is executed; otherwise, step S920 is returned.

[0131] The third duration can be a time value set based on experience.

[0132] In step S940, the first temperature value detected by the first temperature detector and the second temperature value detected by the second temperature detector are obtained.

[0133] In step S950, the temperature difference between the first temperature value and the second temperature value is calculated.

[0134] In step S960, the target opening degree of the throttle valve is obtained based on the temperature difference.

[0135] In step S970, it is determined whether the target opening degree of the throttle valve has reached or exceeded the first opening degree. If so, step S980 is executed; otherwise, step S990 is executed.

[0136] In step S980, the opening of the throttle valve is adjusted to the target opening and maintained for a first duration.

[0137] In step S990, the opening of the throttle valve is adjusted to a first opening degree and maintained for a first duration.

[0138] In step S9100, it is determined whether the second temperature value detected by the second temperature detector reaches or exceeds the temperature threshold. If so, step S9110 is executed; otherwise, step S940 is returned.

[0139] In step S9110, the duration for which the second temperature value reaches or exceeds the temperature threshold is obtained.

[0140] In step S9120, it is determined whether the duration for which the second temperature value reaches or exceeds the temperature threshold reaches or exceeds the second duration. If so, defrosting is exited; otherwise, the process returns to step S9110.

[0141] Understandably, the indoor unit of this application may also include a controller to control the start and stop of the indoor fan and its speed, and to interact with the user, etc., which will not be elaborated here.

[0142] In summary, this application installs a throttling valve 25 on the upper refrigerant pipe 231. The opening of the throttling valve 25 is adjusted by real-time acquisition of the temperature difference between the upper and lower parts of the outdoor heat exchanger 23, specifically the first refrigerant pipe 231 and the second refrigerant pipe 232. This temperature difference reflects the difference in the degree of frost formation between the upper and lower parts of the outdoor heat exchanger 23. Adjusting the opening of the throttling valve 25 accordingly allows for a reasonable distribution of refrigerant between the upper and lower parts of the outdoor heat exchanger 23, improving refrigerant utilization efficiency and thus enhancing defrosting efficiency. Furthermore, the hydrophobic coating on the fins of the outdoor heat exchanger 23 can suppress the rate of frost formation on its surface, thereby reducing the frequency of defrosting. Simultaneously, adjusting the opening of the throttling valve 25 accelerates the melting of frost at the lower part of the outdoor heat exchanger 23, preventing frost from falling from the upper part of the outdoor heat exchanger 23 from accumulating at the lower part, thus ensuring the effective defrosting of the outdoor heat exchanger 23.

[0143] 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 capable of efficient defrosting, characterized in that, include: The refrigerant circulation loop allows the refrigerant to circulate in a loop consisting of a compressor, condenser, throttling device, and evaporator. One of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger. The outdoor heat exchanger includes a first refrigerant line and a second refrigerant line connected in parallel. The first refrigerant line and the second refrigerant line are used to connect between the compressor and the indoor heat exchanger. The first refrigerant line is located above the second refrigerant line. A throttle valve is installed in the first refrigerant line to adjust the refrigerant flow rate in the first refrigerant line; A first temperature detector is installed outside the first refrigerant pipe to detect the temperature outside the first refrigerant pipe. The second temperature detector is located outside the second refrigerant pipe to detect the temperature outside the second refrigerant pipe, and the second temperature detector is located below the midline of the height of the outdoor heat exchanger. The controller, electrically connected to the first temperature detector, the second temperature detector, and the throttle valve, is configured to execute a defrosting strategy, the defrosting strategy including: When defrosting is performed, the first temperature value detected by the first temperature detector and the second temperature value detected by the second temperature detector are obtained; Calculate the temperature difference between the first temperature value and the second temperature value, and adjust the opening of the throttle valve based on the temperature difference. The larger the temperature difference, the smaller the opening of the throttle valve. When the second temperature value detected by the second temperature detector reaches or exceeds the temperature threshold, defrosting is terminated.

2. The air conditioner according to claim 1, characterized in that, Adjusting the opening of the throttle valve based on the temperature difference includes: The target opening of the throttle valve is obtained based on the temperature difference; the larger the temperature difference, the smaller the target opening of the throttle valve. If the target opening degree reaches or exceeds the first opening degree, the opening degree of the throttle valve is adjusted to the target opening degree; otherwise, the opening degree of the throttle valve is adjusted to the first opening degree.

3. The air conditioner according to claim 2, characterized in that, Obtaining the target opening degree of the throttle valve based on the temperature difference includes: The target opening degree of the throttle valve is obtained by querying the mapping table based on the temperature difference. The mapping table contains the mapping relationship between the temperature difference and the target opening degree.

4. The air conditioner according to claim 1, characterized in that, The defrosting strategy includes: After adjusting the opening of the throttle valve based on the temperature difference, the valve is operated at the adjusted opening for a first duration. After running for a first duration at the adjusted throttle valve opening, a step is performed to determine whether the second temperature value detected by the second temperature detector has reached or exceeded the temperature threshold.

5. The air conditioner according to claim 1, characterized in that, The step of exiting defrosting when the second temperature value detected by the second temperature detector reaches or exceeds the temperature threshold includes: When the second temperature value detected by the second temperature detector reaches or exceeds the temperature threshold, the duration for which the second temperature value reaches or exceeds the temperature threshold is obtained; If the duration for which the second temperature value is above the temperature threshold reaches the second duration, then defrosting is terminated.

6. The air conditioner according to claim 1, characterized in that, The defrosting strategy includes: The temperature threshold is determined based on the outdoor ambient temperature where the air conditioner is located, and the temperature threshold is positively correlated with the outdoor ambient temperature.

7. The air conditioner according to claim 1, characterized in that, The defrosting strategy includes: The compressor is continuously running for a certain duration during defrosting. When the duration reaches a third duration or more, the step of obtaining the first temperature value detected by the first temperature detector and the second temperature value detected by the second temperature detector is performed.

8. The air conditioner according to claim 7, characterized in that, The air conditioner includes a four-way valve, the first port of which is connected to the exhaust port of the compressor, the second port of which is connected to the indoor heat exchanger, the third port of which is connected to the outdoor heat exchanger, a throttling device being provided between the outdoor heat exchanger and the indoor heat exchanger, and the fourth port of which is connected to the intake port of the compressor; the defrosting strategy includes: The refrigerant flow direction is controlled by the four-way valve to switch as follows: the refrigerant flows out from the exhaust port of the compressor, flows sequentially through the first port of the four-way valve, the third port of the four-way valve, the outdoor heat exchanger, the throttling device, the indoor heat exchanger, the second port of the four-way valve, and the fourth port of the four-way valve, and then flows back to the compressor through the intake port of the compressor to perform defrosting.

9. The air conditioner according to any one of claims 1 to 8, characterized in that, The first refrigerant pipe and the second refrigerant pipe are provided with fins on their periphery, and the surface of the fins is coated with a hydrophobic coating.

10. A defrosting control method for an air conditioner, characterized in that, The air conditioner is as described in any one of claims 1 to 9, and the defrosting control method includes: Acquire the first temperature value detected by the first temperature detector and the second temperature value detected by the second temperature detector; Calculate the temperature difference between the first temperature value and the second temperature value, and adjust the opening of the throttle valve based on the temperature difference, wherein the larger the temperature difference, the smaller the opening of the throttle valve; Determine whether the second temperature value has reached or exceeded the temperature threshold. If the second temperature value has reached or exceeded the temperature threshold, exit defrosting.

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