Air conditioner outdoor unit capable of efficiently defrosting and air conditioner

Abstract

According to the air conditioner outdoor unit capable of defrosting efficiently and the air conditioner, the surfaces of the fins of the outdoor heat exchanger are coated with the hydrophobic coatings, the surface frosting speed of the outdoor heat exchanger is restrained through the hydrophobic coatings, and meanwhile the heating device is arranged between the outdoor fan and the outdoor heat exchanger; temperature detectors are arranged at different height positions of an outdoor heat exchanger, when defrosting is executed and the temperature of the higher position reaches a first temperature threshold value, air in the lower area of the outdoor heat exchanger is heated through a heating device, and meanwhile heat generated by the heating device is guided to the lower area of the outdoor heat exchanger by means of reverse rotation of an outdoor fan; defrosting of the lower area of the outdoor heat exchanger is accelerated, and the situation that defrosting of the upper area of the outdoor heat exchanger is affected due to the fact that the outdoor fan guides cold air to the upper area of the outdoor heat exchanger is avoided; and the outdoor fan can blow part of frost in the lower area of the outdoor heat exchanger out of the outdoor unit shell. And when the temperature of the lower position reaches a second temperature threshold value, the heating device and the outdoor fan are turned off.

Description

Technical Field

[0001] This application relates to the field of air conditioning technology, and in particular to an outdoor unit and air conditioner capable of efficient defrosting. 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, by coating the fins of an outdoor heat exchanger with a hydrophilic coating, in cooling / dehumidification mode, the hydrophilic coating allows condensate to spread and form a water film on the fins, thereby reducing ventilation resistance and improving heat exchange efficiency. Furthermore, during defrosting, the water formed after the frost melts flows evenly down the fins and is smoothly discharged from the outdoor heat exchanger, preventing water accumulation or ice blockage. However, in low-temperature heating mode, the surface of the outdoor heat exchanger with the hydrophilic coating frosts quickly, requiring frequent defrosting (the defrosting cycle of a typical household air conditioner is usually 40 to 60 minutes). Therefore, some air conditioner outdoor heat exchangers are coated with a hydrophobic coating to suppress the frost formation rate and improve heating performance. However, the surface characteristics of the hydrophobic coating cause the frost to detach in solid form before it completely melts during defrosting, accumulating at the bottom of the outdoor heat exchanger, resulting in a longer defrosting time at the bottom of the outdoor heat exchanger.

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

[0005] To address the aforementioned issues, this application provides an air conditioner outdoor unit capable of efficient defrosting, comprising an outdoor unit housing, an outdoor heat exchanger, an outdoor fan, a heating device, a first temperature detector, a second temperature detector, and a controller. The outdoor unit housing has a receiving chamber. The outdoor heat exchanger is disposed within the receiving chamber, and the fins of the outdoor heat exchanger are coated with a hydrophobic coating. The outdoor fan is disposed within the receiving chamber and opposite the outdoor heat exchanger. The heating device is disposed at the lower part of the receiving chamber, between the outdoor fan and the outdoor heat exchanger, and has a first distance greater than zero between them. The first temperature detector is disposed at a first position on the outdoor heat exchanger. The second temperature detector is disposed at a second position on the outdoor heat exchanger, below the first position and below the midline of the outdoor heat exchanger's height.

[0006] The controller is electrically connected to the first temperature detector, the second temperature detector, the heating device, and the outdoor fan, and is configured to execute a defrosting strategy. The defrosting strategy includes: when defrosting is performed, if the first temperature detector detects that the temperature at the first location reaches or exceeds the first temperature threshold, the heating device is activated to heat the air, and the outdoor fan is controlled to rotate in reverse; if the second temperature detector detects that the temperature at the second location reaches or exceeds the second temperature threshold, the heating device and the outdoor fan are turned off; wherein, when the outdoor fan rotates in reverse, the airflow passes sequentially through the outdoor fan and the outdoor heat exchanger, and is discharged from the outdoor unit casing.

[0007] Thus, in the above technical solution, a hydrophobic coating is applied to the surface of the outdoor heat exchanger fins to suppress the rate of frost formation on the surface of the outdoor heat exchanger. Simultaneously, a heating device is installed between the outdoor fan and the outdoor heat exchanger. A first temperature detector is installed at a first position on the outdoor heat exchanger, and a second temperature detector is installed at a second position below the first position and below the midline of the outdoor heat exchanger's height. During defrosting, the temperature at the first position of the outdoor heat exchanger is detected by the first temperature detector, and the temperature at the second position is detected by the second temperature detector. When the temperature at the first position reaches or exceeds a first temperature threshold... When the frost layer in the upper part of the outdoor heat exchanger has largely melted, the heating device is activated again, and the outdoor fan is reversed. The heating device heats the air in the lower part of the outdoor heat exchanger, and the reverse rotation of the outdoor fan guides the heat generated by the heating device to the lower part of the outdoor heat exchanger, accelerating the melting of the frost layer and shortening the defrosting time in the lower part of the outdoor heat exchanger. This avoids the outdoor fan guiding cold air to the upper part of the outdoor heat exchanger, which would affect the defrosting of the upper part. Furthermore, the outdoor fan can blow some of the frost from the lower part of the outdoor heat exchanger out of the outdoor unit casing, further accelerating defrosting. When the temperature at the second location reaches or exceeds the second temperature threshold, the frost layer in the lower part of the outdoor heat exchanger has melted, and the frost layer in the upper part of the outdoor heat exchanger has also melted. At this point, the heating device and the outdoor fan are turned off. This application shortens the overall defrosting time of the outdoor heat exchanger by coating the fins of the outdoor heat exchanger with a hydrophobic coating and correspondingly optimizing the structural design and defrosting strategy of the outdoor air conditioning unit.

[0008] In some embodiments of this application, the defrosting strategy includes: before starting the heating device, setting the heating power of the heating device based on the outdoor ambient temperature where the outdoor unit of the air conditioner is located, wherein the heating power is negatively correlated with the outdoor ambient temperature.

[0009] In the above technical solution, the heating power of the heating device is set to be related to the outdoor ambient temperature. The lower the outdoor ambient temperature, the greater the heating power of the heating device, which increases the heat provided to the lower area of ​​the outdoor heat exchanger, thereby accelerating the melting of the frost layer in the lower area of ​​the outdoor heat exchanger. The higher the outdoor ambient temperature, the smaller the heating power of the heating device, so that the heat provided by the heating device to the lower area of ​​the outdoor heat exchanger is matched with the defrosting demand, avoiding heat waste and reducing the energy consumption of the air conditioner.

[0010] In some embodiments of this application, the heating power of the heating device is set based on the outdoor ambient temperature where the outdoor unit of the air conditioner is located, including: when the outdoor ambient temperature where the outdoor unit of the air conditioner is located is below a third temperature threshold, the heating power of the heating device is set to a first power; when the outdoor ambient temperature where the outdoor unit of the air conditioner is located reaches or exceeds the third temperature threshold but is below a fourth temperature threshold, the heating power of the heating device is set to a second power, the second power being less than the first power; when the outdoor ambient temperature where the outdoor unit of the air conditioner is located reaches or exceeds the fourth temperature threshold, the heating power of the heating device is set to a third power, the third power being less than the second power.

[0011] In the above technical solution, the heating power of the heating device is divided into three levels. When the outdoor ambient temperature where the air conditioner outdoor unit is located is below the third temperature threshold, the heating power of the heating device is set to the first power of the maximum level. When the outdoor ambient temperature where the air conditioner outdoor unit is located reaches or exceeds the third temperature threshold but is below the fourth temperature threshold, the heating power of the heating device is set to the second power of the medium level. When the outdoor ambient temperature where the air conditioner outdoor unit is located reaches or exceeds the fourth temperature threshold, the heating power of the heating device is set to the third power of the minimum level. By dividing the power into levels, the control logic of the heating device can be simplified.

[0012] In some embodiments of this application, the defrosting strategy includes: before controlling the outdoor fan to rotate in reverse, setting the reverse rotation speed of the outdoor fan based on the outdoor ambient temperature where the outdoor unit of the air conditioner is located, wherein the reverse rotation speed is positively correlated with the outdoor ambient temperature.

[0013] In the above technical solution, the reverse rotation speed of the outdoor fan is set to be related to the outdoor ambient temperature. The lower the outdoor ambient temperature, the lower the reverse rotation speed of the outdoor fan, which reduces the impact of low temperature air on the upper part of the outdoor heat exchanger and reduces the energy consumption of the outdoor fan. The higher the outdoor ambient temperature, the higher the reverse rotation speed of the outdoor fan, which speeds up the delivery of heat generated by the heating device to the lower part of the outdoor heat exchanger, thereby accelerating the melting of frost in the lower part of the outdoor heat exchanger.

[0014] In some embodiments of this application, if the first temperature detector detects that the temperature at the first location reaches or exceeds a first temperature threshold, then the heating device is activated to heat the area, and the outdoor fan is controlled to rotate in the reverse direction. This includes: if the first temperature detector detects that the temperature at the first location reaches or exceeds the first temperature threshold, then the duration for which the temperature at the first location reaches or exceeds the first temperature threshold is obtained; if the duration for which the temperature at the first location reaches or exceeds the first temperature threshold is greater than a first duration, then the heating device is activated, and the outdoor fan is controlled to rotate in the reverse direction.

[0015] In the above technical solution, the heating device is activated and the outdoor fan is controlled to rotate in reverse only when the temperature at the first position reaches or exceeds the first temperature threshold for a duration of more than a first time. This can prevent the outdoor fan from being mistakenly activated in reverse rotation due to instantaneous temperature fluctuations before the temperature at the first position of the outdoor heat exchanger has stabilized and reached or exceeded the first temperature threshold, thus affecting the defrosting process of the area at and above the first position of the outdoor heat exchanger.

[0016] In some embodiments of this application, if the second temperature detector detects that the temperature at the second location reaches or exceeds the second temperature threshold, then the heating device and the outdoor fan are turned off, including: if the second temperature detector detects that the temperature at the second location reaches or exceeds the second temperature threshold, then the duration for which the temperature at the second location reaches or exceeds the second temperature threshold is obtained; if the duration for which the temperature at the second location reaches or exceeds the second temperature threshold is a second duration or more, then the heating device and the outdoor fan are turned off.

[0017] In the above technical solution, the heating device and outdoor fan are turned off only when the temperature at the second position reaches or exceeds the second temperature threshold for a duration of more than the second time. This can avoid the outdoor fan and heating device being turned off erroneously due to instantaneous temperature fluctuations before the temperature at the second position of the outdoor heat exchanger has stabilized and reached or exceeded the second temperature threshold, thus affecting the defrosting effect of the area at and below the second position of the outdoor heat exchanger.

[0018] In some embodiments of this application, the outdoor unit of the air conditioner includes a compressor disposed in a housing chamber; the defrosting strategy includes: obtaining the continuous running time of the compressor during defrosting, and when the running time reaches a third duration or more, performing the step of determining whether the temperature detected by the first temperature detector at the first location has reached a first temperature threshold or more.

[0019] In the above technical solution, when the compressor runs continuously for more than three hours during defrosting, the temperature at the first position detected by the first temperature detector is obtained, and it is determined whether it has reached or exceeded the first temperature threshold, which can reduce unnecessary processing logic.

[0020] In some embodiments of this application, the outdoor unit of the air conditioner includes a four-way valve. The first port of the four-way valve is connected to the discharge port of the compressor, the second port of the four-way valve is connected to the indoor heat exchanger, the third port of the four-way valve is connected to the outdoor heat exchanger, a throttling device is provided between the outdoor heat exchanger and the indoor heat exchanger, and the fourth port of the four-way valve is connected to the inlet of the compressor. The defrosting strategy includes controlling the four-way valve to switch the refrigerant flow direction so that it flows out from the discharge 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 inlet of the compressor 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 first spacing is 20 mm to 50 mm.

[0023] In the above technical solution, a distance of more than 20 mm is maintained between the heating device and the outdoor heat exchanger to keep the heating device away from the frost area of ​​the outdoor heat exchanger and reduce the probability of contact between the heating device and the frost layer and defrosting water; a distance of less than 50 mm is maintained between the heating device and the outdoor heat exchanger to avoid large heat loss due to excessive distance, which would affect the defrosting effect.

[0024] In some embodiments of this application, the outdoor unit housing has a chassis, the chassis is configured with a water tank and a drain hole, the drain hole connects the water tank and the outside of the outdoor unit housing, the outdoor heat exchanger is disposed on the chassis, and the lowest point of the heating device and the lowest point of the water tank have a second distance, the second distance being greater than or equal to 5 mm.

[0025] In the above technical solution, the lowest point of the heating device is set to form a distance of 5 mm or more from the lowest point of the water tank of the outdoor unit chassis. This reduces the probability of the heating device coming into contact with the defrosting water accumulated on the chassis, and avoids energy loss caused by contact with liquid water, which would affect the defrosting effect.

[0026] This application also provides an air conditioner including an indoor unit and an outdoor unit. The indoor unit has an indoor heat exchanger and an indoor fan, and is used to regulate indoor air. The outdoor unit is as described above.

[0027] In the above technical solution, by coating the fins of the outdoor heat exchanger with a hydrophobic coating and optimizing the structure and defrosting strategy of the outdoor air conditioning unit accordingly, the overall defrosting time of the outdoor heat exchanger is shortened.

[0028] 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

[0029] 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.

[0030] Figure 1 A schematic diagram of the structure of an air conditioner according to an embodiment of this application is shown.

[0031] Figure 2 A schematic diagram of the structure of an outdoor unit of an air conditioner according to an embodiment of this application is shown.

[0032] Figure 3 A schematic diagram showing the installation orientation of a temperature detector according to an embodiment of this application is provided.

[0033] Figure 4 A block diagram of an air conditioner electronic control system according to an embodiment of this application is shown.

[0034] Figure 5 A flowchart illustrating a defrosting strategy according to an embodiment of this application is shown.

[0035] Figure 6 A detailed flowchart of the steps for determining the heating power of a heating device according to an embodiment of this application is shown.

[0036] Figure 7 A flowchart illustrating another embodiment of the defrosting strategy of this application is shown.

[0037] Figure 8 A detailed flowchart of the temperature determination step at the first position according to an embodiment of this application is shown.

[0038] Figure 9 A detailed flowchart of the temperature determination step at the second position according to an embodiment of this application is shown.

[0039] Figure 10 A flowchart illustrating a defrosting strategy according to yet another embodiment of this application is shown.

[0040] 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; 24. Outdoor fan; 25. Heating device; 261. First temperature detector; 262. Second temperature detector; 27. Controller; 28. Throttling device; 29. ​​Chassis. Detailed Implementation

[0041] 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.

[0042] 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.

[0043] In the description of this application, it should be understood that the terms "top", "bottom", "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.

[0044] 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.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "set up," "connected," and "linked" 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.

[0046] 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.

[0047] In related technologies, there is a problem with the long defrosting time at the bottom of the outdoor heat exchanger in the outdoor unit of the air conditioner. The reason is that the surface of the fins of the outdoor heat exchanger is coated with a hydrophobic coating. The surface characteristics of the hydrophobic coating cause the frost layer to fall off in solid form before it is completely melted during the defrosting process and accumulate at the bottom of the outdoor heat exchanger.

[0048] In view of this, this application coats the fins of the outdoor heat exchanger with a hydrophobic coating to suppress the rate of frost formation on the surface of the outdoor heat exchanger. Simultaneously, a heating device is installed between the outdoor fan and the outdoor heat exchanger. A first temperature detector is installed at a first position on the outdoor heat exchanger, and a second temperature detector is installed at a second position below the first position and below the midline of the outdoor heat exchanger's height. During defrosting, the temperature at the first position of the outdoor heat exchanger is detected by the first temperature detector, and the temperature at the second position is detected by the second temperature detector. When the temperature at the first position reaches or exceeds a first temperature threshold... Once the frost layer in the upper part of the outdoor heat exchanger has largely melted, the heating device is activated again, and the outdoor fan is reversed. The heating device heats the air in the lower part of the outdoor heat exchanger, while the reverse rotation of the outdoor fan directs the heat generated by the heating device to the lower part of the heat exchanger, accelerating the melting of the frost layer and shortening the defrosting time in this area. This avoids the outdoor fan directing cold air to the upper part of the heat exchanger, which would otherwise hinder defrosting in that area. Furthermore, the outdoor fan can blow some of the frost from the lower part of the heat exchanger out of the outdoor unit casing, further accelerating defrosting. When the temperature at the second location reaches or exceeds the second temperature threshold, the frost layer in the lower part of the outdoor heat exchanger has melted, and the frost layer in the upper part has also melted. At this point, the heating device and outdoor fan are turned off. By coating the fins of the outdoor heat exchanger with a hydrophobic coating and optimizing the structure and defrosting strategy of the outdoor unit, the overall defrosting time of the outdoor heat exchanger is shortened.

[0049] 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.

[0050] Figure 1 A schematic diagram of the structure of an air conditioner according to an embodiment of this application is shown. Figure 2 A schematic diagram of the structure of an outdoor unit of an air conditioner according to an embodiment of this application is shown.

[0051] Air conditioners execute a cooling / heating cycle using a compressor, condenser, expansion valve, and evaporator. This cycle involves a series of processes: compression, condensation, expansion, and evaporation. The compressor compresses refrigerant gas at high temperature and pressure and discharges the compressed 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. The expansion valve 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 valve, returning the low-temperature, low-pressure refrigerant gas to the compressor. The evaporator achieves its 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] In some embodiments, such as Figure 2As shown, the outdoor unit housing has a chassis 29, side panels (not shown in the figure), and a top cover (not shown in the figure). The chassis 29 and the top cover are arranged opposite each other and are respectively connected to the upper and lower ends of the side panels. The chassis 29, side panels, and top cover enclose a receiving chamber. The chassis 29 is constructed with a water tank (not shown in the figure) and a drain hole (not shown in the figure). The water tank is used to collect defrost water, and the drain hole connects the water tank to the outside of the outdoor unit housing to discharge the defrost water in the water tank to the outdoor unit.

[0058] like Figure 1 and Figure 2 As shown, the outdoor unit also includes a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, an outdoor fan 24, and a heating device 25. The compressor 21, the four-way valve 22, the outdoor heat exchanger 23, the outdoor fan 24, and the heating device 25 are all located in the receiving cavity of the outdoor unit casing structure.

[0059] The compressor 21 is used to compress the refrigerant. The first port of the four-way valve 22 is connected to the discharge 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 inlet port of the compressor 21. By controlling the four-way valve 22, the flow direction of the refrigerant can be switched.

[0060] In cooling mode, the refrigerant is compressed by compressor 21 and flows out from the discharge 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 inlet of compressor 21 through four-way valve 22, completing the refrigeration cycle. In heating mode, the refrigerant is compressed by compressor 21 and flows out from the discharge 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 inlet of compressor 21 through four-way valve 22, completing the heating cycle.

[0061] In some embodiments, the throttling device 28 may be a capillary tube. In some embodiments, the throttling device 28 may be an expansion valve.

[0062] In some embodiments, the outdoor heat exchanger 23 is a vertical heat exchanger. The outdoor heat exchanger 23 is mounted on a chassis 29. The fins of the outdoor heat exchanger 23 are coated with a hydrophobic coating.

[0063] In some embodiments, the outdoor fan 24 is disposed opposite to the outdoor heat exchanger 23. The outdoor fan 24 has a first rotation direction. In cooling mode, the outdoor fan 24 operates in the first rotation direction, causing air to flow through the fins of the outdoor heat exchanger 23, carrying away the heat of the outdoor heat exchanger 23 and helping the refrigerant dissipate heat. In heating mode, the outdoor fan 24 operates in the first rotation direction, drawing 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.

[0064] In some embodiments, the outdoor fan 24 also has a second rotation direction, which is opposite to the first rotation direction (forward rotation). When the outdoor fan 24 operates in the second rotation direction, the airflow passes sequentially through the outdoor fan 24 and the outdoor heat exchanger 23, and is discharged outward from the outdoor unit casing.

[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] In some embodiments, the heating device 25 is an electric heating device. The heating power of the heating device 25 is adjustable.

[0067] In some embodiments, the heating device 25 is disposed in the lower part of the receiving chamber, the heating device 25 is located between the outdoor fan 24 and the outdoor heat exchanger 23, and has a first distance from the outdoor heat exchanger 23, the first distance being greater than zero.

[0068] The heating device 25 is located between the outdoor fan 24 and the outdoor heat exchanger 23. When the outdoor fan 24 is operating in the second direction, it can blow the airflow heated by the heating device 25 toward the outdoor heat exchanger 23. There is a first gap between the heating device 25 and the outdoor heat exchanger 23, which helps to avoid the frost area of ​​the outdoor heat exchanger 23.

[0069] In some embodiments, the first spacing is 20 mm to 50 mm. Maintaining a spacing of 20 mm or more between the heating device 25 and the outdoor heat exchanger 23 avoids the frost-prone area of ​​the outdoor heat exchanger 23, reducing the probability of contact between the heating device 25 and the frost layer and defrosting water. Maintaining a spacing of less than 50 mm between the heating device 25 and the outdoor heat exchanger 23 avoids excessive heat loss due to excessive distance, which could affect the defrosting effect.

[0070] In some embodiments, the lowest point of the heating device 25 is flush with the lowest point of the outdoor heat exchanger 23. This reduces the probability of the heating device 25 coming into contact with defrost water.

[0071] In some embodiments, the lowest point of the heating device 25 is slightly lower than the lowest point of the outdoor heat exchanger 23, which may be a second distance from the lowest point of the outdoor heat exchanger 23, for example, less than or equal to 5 mm, in order to reduce the probability of the heating device 25 coming into contact with defrost water.

[0072] In some embodiments, the outdoor heat exchanger 23 is disposed on the outdoor unit chassis 29, and the lowest point of the heating device 25 and the lowest point of the water tank of the outdoor unit chassis 29 have a second distance, which is greater than or equal to 5 mm.

[0073] The lowest point of the heating device 25 and the lowest point of the water tank of the outdoor unit chassis 29 form a distance of 5 mm or more, which reduces the probability of the heating device 25 and the chassis 29 accumulating defrost water contacting each other, and avoids energy loss caused by contact with liquid water, thus affecting the defrosting effect.

[0074] In the above embodiments, by rationally designing the installation position of the heating device 25, the heating device 25 is effectively avoided from the frost area of ​​the outdoor heat exchanger 23, reducing the probability of contact between the heating device 25 and the frost layer and defrosting water, and rationally controlling the heat loss in the heat conduction process; at the same time, the probability of contact between the heating device 25 and the defrosting water accumulated on the chassis 29 is reduced, avoiding energy loss caused by contact with liquid water, thereby ensuring the defrosting effect.

[0075] Figure 3 A schematic diagram showing the installation orientation of a temperature detector according to an embodiment of this application is provided.

[0076] The outdoor unit also includes a first temperature detector 261 and a second temperature detector 262, which are located at different heights of the outdoor heat exchanger 23 to detect the temperature at their respective heights.

[0077] In some embodiments, such as Figure 3 As shown, the first temperature detector 261 is located at the first position of the outdoor heat exchanger 23, and the second temperature detector 262 is located at the second position of the outdoor heat exchanger 23. The second position is located below the first position and below the midline of the height of the outdoor heat exchanger 23.

[0078] In some embodiments, the first position is the upper middle position of the outdoor heat exchanger 23, that is, the first temperature detector 261 is disposed at the upper middle position of the outdoor heat exchanger 23; the second position is the lower position of the outdoor heat exchanger 23, that is, the second temperature detector 262 is disposed at the lower position of the outdoor heat exchanger 23.

[0079] 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 at the first position. 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 of the first position, or the median value of the temperature data detected by the multiple temperature sensors may be used as the temperature of the first position.

[0080] 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 at the second position. 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 of the second position, or the median value of the temperature data detected by the multiple temperature sensors may be used as the temperature of the second position.

[0081] Figure 4 A block diagram of an air conditioner electronic control system according to an embodiment of this application is shown.

[0082] 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 by starting and stopping compressor 21. Controller 27 can be electrically connected to each temperature sensor, and can receive temperature signals from each sensor and control 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, stop, and direction. Controller 27 can be electrically connected to heating device 25, and can send control signals to heating device 25 to control its start, stop, and heating power. 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 refrigerant flow direction, thereby realizing a series of control processes for the air conditioner.

[0083] Controller 27 is configured to execute a defrosting strategy, such as Figure 5 As shown, the defrosting strategy includes at least steps S510 to S560, which are described in detail below.

[0084] In step S510, when defrosting is performed, the temperature information of the first position detected by the first temperature detector is obtained.

[0085] In step S520, it is determined whether the temperature detected by the first temperature detector at the first position reaches or exceeds the first temperature threshold. If so, step S530 is executed; otherwise, step S510 is returned.

[0086] The first temperature threshold is a temperature value set based on experience.

[0087] In some embodiments, the first temperature threshold corresponds to the temperature at which the first position has completed or is close to completing defrosting. When the first temperature detector detects that the temperature at the first position has reached or exceeded the first temperature threshold, the area at and above the first position of the outdoor heat exchanger has completed or is close to completing defrosting. When the first temperature detector detects that the temperature at the first position has not yet reached or exceeded the first temperature threshold, the area at and above the first position of the outdoor heat exchanger has not yet completed or is close to completing defrosting.

[0088] In step S530, the heating device is started to heat up, and the outdoor fan is controlled to rotate in reverse.

[0089] In step S540, the temperature information of the second location detected by the second temperature detector is obtained.

[0090] In step S550, it is determined whether the temperature detected by the second temperature detector at the second position reaches or exceeds the second temperature threshold. If so, step S560 is executed; otherwise, step S540 is returned.

[0091] The second temperature threshold is a temperature value set based on experience.

[0092] In some embodiments, the second temperature threshold corresponds to the temperature at which the second position has completed or is close to completing defrosting. When the second temperature detector detects that the temperature at the second position has reached or exceeded the second temperature threshold, the area of ​​the outdoor heat exchanger at or above the second position has completed or is close to completing defrosting. When the second temperature detector detects that the temperature at the second position has not yet reached or exceeded the second temperature threshold, the area of ​​the outdoor heat exchanger at or below the second position has not yet completed or is close to completing defrosting.

[0093] In step S560, the heating device and the outdoor fan are turned off.

[0094] exist Figure 5In the illustrated embodiment, when the area above the first position of the outdoor heat exchanger has completed or is nearly completed defrosting, the heating device is activated, and the outdoor fan is controlled to rotate in reverse. The heating device heats the air in the lower area of ​​the outdoor heat exchanger, and the reverse rotation of the outdoor fan guides the heat generated by the heating device to the lower area of ​​the outdoor heat exchanger, accelerating the melting of frost and shortening the defrosting time. This avoids the outdoor fan guiding cold air to the area above the first position of the outdoor heat exchanger, which would affect the defrosting of that area. Furthermore, the outdoor fan can also blow some of the frost from the lower area of ​​the outdoor heat exchanger out of the outdoor unit casing, further accelerating defrosting. When the area above the second position of the outdoor heat exchanger has completed or is nearly completed defrosting, the heating device and outdoor fan are turned off, ensuring effective defrosting.

[0095] In some embodiments, the defrosting strategy includes: setting the heating power of the heating device based on the outdoor ambient temperature where the outdoor unit of the air conditioner is located before starting the heating device, wherein the heating power is negatively correlated with the outdoor ambient temperature.

[0096] By setting the heating power of the heating device to be related to the outdoor ambient temperature, the lower the outdoor ambient temperature, the greater the heating power of the heating device, increasing the heat provided to the lower area of ​​the outdoor heat exchanger, thereby accelerating the melting of the frost layer in the lower area of ​​the outdoor heat exchanger; the higher the outdoor ambient temperature, the smaller the heating power of the heating device, so that the heat provided by the heating device to the lower area of ​​the outdoor heat exchanger is matched with the defrosting needs, avoiding heat waste and reducing the energy consumption of the air conditioner.

[0097] In some embodiments, such as Figure 6 As shown, the heating power of the heating device is set based on the outdoor ambient temperature where the outdoor unit of the air conditioner is located, which includes at least steps S610 to S650, as detailed below.

[0098] In step S610, it is determined whether the outdoor ambient temperature where the outdoor unit of the air conditioner is located is below the third temperature threshold. If so, step S620 is executed; otherwise, step S630 is executed.

[0099] In step S620, the heating power of the heating device is set to the first power.

[0100] In step S630, it is determined whether the outdoor ambient temperature where the outdoor unit of the air conditioner is located reaches or exceeds the third temperature threshold and is below the fourth temperature threshold. If so, step S640 is executed; otherwise, step S650 is executed.

[0101] The third temperature threshold is a temperature value set based on experience. The fourth temperature threshold is also a temperature value set based on experience, and the fourth temperature threshold is greater than the third temperature threshold.

[0102] In step S640, the heating power of the heating device is set to a second power, which is less than the first power.

[0103] In step S650, the heating power of the heating device is set to a third power, which is less than the second power.

[0104] exist Figure 6 In the illustrated embodiment, the heating power of the heating device is divided into three levels. When the outdoor ambient temperature where the air conditioner outdoor unit is located is below the third temperature threshold, the heating power of the heating device is set to the maximum level (first power). When the outdoor ambient temperature where the air conditioner outdoor unit is located reaches or exceeds the third temperature threshold but is below the fourth temperature threshold, the heating power of the heating device is set to the medium level (second power). When the outdoor ambient temperature where the air conditioner outdoor unit is located reaches or exceeds the fourth temperature threshold, the heating power of the heating device is set to the minimum level (third power). By dividing the power into levels, the control logic of the heating device can be simplified.

[0105] In some embodiments, the defrosting strategy includes: before controlling the outdoor fan to rotate in reverse, setting the reverse rotation speed of the outdoor fan based on the outdoor ambient temperature where the outdoor unit of the air conditioner is located, wherein the reverse rotation speed is positively correlated with the outdoor ambient temperature.

[0106] By setting the reverse rotation speed of the outdoor fan to be related to the outdoor ambient temperature, the lower the outdoor ambient temperature, the lower the reverse rotation speed of the outdoor fan, reducing the impact of low-temperature air on the upper part of the outdoor heat exchanger and reducing the energy consumption of the outdoor fan; the higher the outdoor ambient temperature, the higher the reverse rotation speed of the outdoor fan, accelerating the delivery of heat generated by the heating device to the lower part of the outdoor heat exchanger, thereby accelerating the melting of frost in the lower part of the outdoor heat exchanger.

[0107] In some embodiments, such as Figure 7 As shown, the defrosting strategy includes at least steps S710 to S7110, which are described in detail below.

[0108] In step S710, the four-way valve is controlled to switch the refrigerant flow direction to the defrosting mode in order to perform defrosting.

[0109] 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 discharge 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 inlet port to perform defrosting.

[0110] In step S720, the temperature information of the first location detected by the first temperature detector is obtained.

[0111] In step S730, it is determined whether the temperature detected by the first temperature detector at the first position reaches or exceeds the first temperature threshold. If so, step S740 is executed; otherwise, step S720 is returned.

[0112] In step S740, it is determined whether the outdoor ambient temperature where the outdoor unit of the air conditioner is located is below the third temperature threshold. If so, step S750 is executed; otherwise, step S760 is executed.

[0113] In step S750, the heating device is controlled to operate at a first power, and the outdoor fan is controlled to rotate in the opposite direction at a first speed.

[0114] In step S760, it is determined whether the outdoor ambient temperature where the outdoor unit of the air conditioner is located reaches or exceeds the third temperature and is below the fourth temperature threshold. If so, step S770 is executed; otherwise, step S780 is executed.

[0115] In step S770, the heating device is controlled to operate at a second power, and the outdoor fan is controlled to rotate in the opposite direction at a second speed. The second power is less than the first power, and the second speed is greater than the first speed.

[0116] In step S780, the heating device is controlled to operate at a third power, and the outdoor fan is controlled to rotate in the opposite direction at a third speed. The third power is less than the second power, and the third speed is greater than the second speed.

[0117] In step S790, the temperature information of the second location detected by the second temperature detector is obtained.

[0118] In step S7100, it is determined whether the temperature detected by the second temperature detector at the second position reaches or exceeds the second temperature threshold. If so, step S7110 is executed; otherwise, step S790 is returned.

[0119] In step S7110, the heating device and the outdoor fan are turned off.

[0120] exist Figure 7 In the illustrated embodiment, the heating power of the heating device and the reverse rotation speed of the outdoor fan are correlated with the outdoor ambient temperature. A dynamic balance between system defrosting efficiency and energy consumption control under low-temperature conditions is achieved through the coordinated adjustment of both airflow and heat source parameters. Specifically, the reverse rotation speed of the outdoor fan is positively correlated with the outdoor ambient temperature; the lower the outdoor ambient temperature, the lower the reverse rotation speed of the outdoor fan during operation, thus reducing the interference of cold outdoor air on the defrosting process in the upper and middle areas of the outdoor heat exchanger. The heating power of the heating device is inversely correlated with the outdoor ambient temperature; the lower the outdoor ambient temperature, the higher the heating power of the heating device, thus accelerating the defrosting process in the lower area of ​​the outdoor heat exchanger.

[0121] In some embodiments, if the first temperature detector detects that the temperature at the first location reaches or exceeds a first temperature threshold, it further determines the duration for which the temperature at the first location has exceeded the first temperature threshold, in order to avoid misjudgment of temperature due to temporary temperature fluctuations. Figure 8 As shown, the determination steps for whether the temperature at the first position reaches the first temperature threshold include at least the following steps S810 to S840, which are described in detail below.

[0122] In step S810, it is determined whether the temperature detected by the first temperature detector at the first location reaches or exceeds the first temperature threshold. If so, step S820 is executed.

[0123] In step S820, the duration for which the temperature at the first location reaches or exceeds a first temperature threshold is obtained. Then, step S830 is executed.

[0124] In step S830, it is determined whether the duration for which the temperature at the first location has reached or exceeded the first temperature threshold has exceeded the first duration. If so, step S840 is executed; otherwise, step S820 is returned.

[0125] The first duration can be a time value set based on experience.

[0126] In step S840, the heating device is started and the outdoor fan is controlled to rotate in reverse.

[0127] exist Figure 8 In the illustrated embodiment, if the first temperature detector detects that the temperature at the first location has reached or exceeded the first temperature threshold, the duration for which the temperature at the first location has reached or exceeded the first temperature threshold is further obtained. The heating device is activated only when the duration for which the temperature at the first location has reached or exceeded the first temperature threshold reaches or exceeds the first duration, and the outdoor fan is controlled to rotate in reverse. This can avoid the outdoor fan being mistakenly activated in reverse rotation due to instantaneous temperature fluctuations before the temperature at the first location of the outdoor heat exchanger has stabilized and reached or exceeded the first temperature threshold, thus affecting the defrosting process of the area at and above the first location of the outdoor heat exchanger.

[0128] In some embodiments, if the second temperature detector detects that the temperature at the second location reaches or exceeds a second temperature threshold, it further determines the duration for which the temperature at the second location has exceeded the second temperature threshold, in order to avoid misjudgment of temperature due to temporary temperature fluctuations. Figure 9 As shown, the determination steps for whether the temperature at the second position reaches the second temperature threshold include at least the following steps S910 to S940, which are described in detail below.

[0129] In step S910, it is determined whether the temperature detected by the second temperature detector at the second position reaches or exceeds the second temperature threshold. If so, step S920 is executed.

[0130] In step S920, the duration for which the temperature at the second location reaches or exceeds the second temperature threshold is obtained. Then, step S930 is executed.

[0131] In step S930, it is determined whether the duration for which the temperature at the second position reaches or exceeds the second temperature threshold has reached or exceeded the second duration. If so, step S940 is executed; otherwise, step S920 is returned.

[0132] The second duration can be a time value set based on experience.

[0133] In step S940, the heating device and the outdoor fan are turned off.

[0134] exist Figure 9 In the illustrated embodiment, if the second temperature detector detects that the temperature at the second location has reached or exceeded the second temperature threshold, the duration for which the temperature at the second location has reached or exceeded the second temperature threshold is further obtained. The heating device and the outdoor fan are only turned off when the duration for which the temperature at the second location has reached or exceeded the second time period. This can avoid the outdoor fan and heating device being mistakenly turned off due to instantaneous temperature fluctuations before the temperature at the second location of the outdoor heat exchanger has stabilized and reached or exceeded the second temperature threshold, thus affecting the defrosting effect of the area at and below the second location of the outdoor heat exchanger.

[0135] In some embodiments, the defrosting strategy further includes: obtaining the continuous running time of the compressor during defrosting, and when the running time reaches a third duration or more, performing the step of determining whether the temperature detected by the first temperature detector at the first location has reached or exceeded the first temperature threshold.

[0136] like Figure 10 As shown, the defrosting strategy includes at least steps S1010 to S1090, which are described in detail below.

[0137] In step S1010, the four-way valve is controlled to switch the refrigerant flow direction to the defrosting mode in order to perform defrosting.

[0138] 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 discharge 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 inlet port to perform defrosting.

[0139] In step S1020, the runtime of the compressor during continuous operation when defrosting is obtained.

[0140] In step S1030, it is determined whether the compressor's running time has reached the third duration or more. If so, step S1040 is executed; otherwise, step S1020 is returned.

[0141] The third duration can be a time value set based on experience.

[0142] In step S1040, the temperature information of the first location detected by the first temperature detector is obtained.

[0143] In step S1050, it is determined whether the temperature detected by the first temperature detector at the first position reaches or exceeds the first temperature threshold. If so, step S1060 is executed; otherwise, step S1040 is returned.

[0144] In step S1060, the heating device is started to heat the air, and the outdoor fan is controlled to rotate in reverse.

[0145] In step S1070, the temperature information of the second position detected by the second temperature detector is obtained.

[0146] In step S1080, it is determined whether the temperature detected by the second temperature detector at the second position reaches or exceeds the second temperature threshold. If so, step S1090 is executed; otherwise, step S1070 is returned.

[0147] In step S1090, the heating device and the outdoor fan are turned off.

[0148] exist Figure 10 In the embodiment shown, when the compressor has been running continuously for more than three hours during defrosting, the temperature at the first location detected by the first temperature detector is obtained, and it is determined whether it has reached or exceeded the first temperature threshold, which can reduce unnecessary processing logic.

[0149] 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.

[0150] In summary, this application controls the outdoor fan to rotate in reverse and activates the heating device during the defrosting process of the outdoor heat exchanger. The fan's reverse rotation blows the detached frost away from the outside of the outdoor heat exchanger, reducing its accumulation on the outdoor unit chassis and the bottom of the outdoor heat exchanger. Simultaneously, the reverse rotation of the outdoor fan guides the heat generated by the heating device to the lower area of ​​the outdoor heat exchanger, accelerating the melting of frost in this area through hot air circulation, thereby shortening the overall defrosting time. Furthermore, by detecting the temperature at the upper-middle position of the outdoor heat exchanger, the defrosting completion status of the upper and middle areas is determined. Only after confirming that defrosting in the upper and middle areas of the outdoor heat exchanger is complete is the outdoor fan controlled to rotate in reverse to avoid interfering with the defrosting process in these areas. In addition, by rationally designing the installation position of the heating device, the heating device can effectively avoid the frost area of ​​the outdoor heat exchanger and reduce the probability of the heating device coming into contact with frost and defrosting water. This can not only ensure the defrosting effect of the lower area of ​​the outdoor heat exchanger, but also reduce the ineffective energy consumption caused by the heating device coming into contact with frost or defrosting water, thereby improving the system energy efficiency.

[0151] 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 outdoor unit capable of efficient defrosting, characterized in that, include: The outdoor unit casing has a accommodating chamber. An outdoor heat exchanger is disposed in the receiving chamber, and the fin surface of the outdoor heat exchanger is coated with a hydrophobic coating. An outdoor fan is installed in the receiving chamber and is opposite to the outdoor heat exchanger; A heating device is disposed in the lower part of the receiving chamber. The heating device is located between the outdoor fan and the outdoor heat exchanger and has a first distance from the outdoor heat exchanger, the first distance being greater than zero. A first temperature detector is installed at a first location on the outdoor heat exchanger; A second temperature detector is disposed at a second position on the outdoor heat exchanger, the second position being located below the first position and below the midline of the height of the outdoor heat exchanger; The controller, electrically connected to the first temperature detector, the second temperature detector, the heating device, and the outdoor fan, is configured to execute a defrosting strategy, the defrosting strategy including: When defrosting is performed, if the first temperature detector detects that the temperature at the first location has reached or exceeded the first temperature threshold, the heating device is activated to heat the air, and the outdoor fan is controlled to rotate in reverse. If the second temperature detector detects that the temperature at the second location has reached or exceeded the second temperature threshold, then the heating device and the outdoor fan are turned off. When the outdoor fan rotates in reverse, the airflow passes through the outdoor fan and the outdoor heat exchanger in sequence and is discharged outward from the outdoor unit casing.

2. The outdoor unit of the air conditioner according to claim 1, characterized in that, The defrosting strategy includes: Before starting the heating device, the heating power of the heating device is set based on the outdoor ambient temperature where the outdoor unit of the air conditioner is located, and the heating power is negatively correlated with the outdoor ambient temperature.

3. The outdoor unit of the air conditioner according to claim 2, characterized in that, Setting the heating power of the heating device based on the outdoor ambient temperature where the outdoor unit of the air conditioner is located includes: When the outdoor ambient temperature of the outdoor unit of the air conditioner is below the third temperature threshold, the heating power of the heating device is set to the first power. When the outdoor ambient temperature of the outdoor unit of the air conditioner reaches or exceeds the third temperature threshold but is below the fourth temperature threshold, the heating power of the heating device is set to the second power, which is less than the first power. When the outdoor ambient temperature where the outdoor unit of the air conditioner is located reaches or exceeds the fourth temperature threshold, the heating power of the heating device is set to the third power, which is less than the second power.

4. The outdoor unit of the air conditioner according to claim 1, characterized in that, The defrosting strategy includes: Before controlling the outdoor fan to rotate in reverse, the reverse rotation speed of the outdoor fan is set based on the outdoor ambient temperature where the outdoor unit of the air conditioner is located, and the reverse rotation speed is positively correlated with the outdoor ambient temperature.

5. The outdoor unit of the air conditioner according to claim 1, characterized in that, If the first temperature detector detects that the temperature at the first location reaches or exceeds a first temperature threshold, then the heating device is activated to heat the air, and the outdoor fan is controlled to rotate in reverse, including: If the first temperature detector detects that the temperature at the first location reaches or exceeds the first temperature threshold, then the duration for which the temperature at the first location reaches or exceeds the first temperature threshold is obtained. If the temperature at the first location remains above the first temperature threshold for a duration of more than the first duration, the heating device is activated and the outdoor fan is controlled to rotate in the opposite direction. and / or If the second temperature detector detects that the temperature at the second location reaches or exceeds the second temperature threshold, then shutting off the heating device and the outdoor fan includes: If the second temperature detector detects that the temperature at the second location has reached or exceeded the second temperature threshold, then the duration for which the temperature at the second location has reached or exceeded the second temperature threshold is obtained. If the temperature at the second location remains above the second temperature threshold for a duration exceeding the second time limit, then the heating device and the outdoor fan shall be turned off.

6. The outdoor unit of the air conditioner according to claim 1, characterized in that, The outdoor unit of the air conditioner includes a compressor, which is disposed within the receiving cavity; 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 determining whether the temperature detected by the first temperature detector at the first location has reached or exceeded a first temperature threshold is executed.

7. The outdoor unit of the air conditioner according to claim 6, characterized in that, The outdoor unit of the air conditioner includes a four-way valve. The first port of the four-way valve is connected to the exhaust port of the compressor, 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 heat exchanger and the indoor heat exchanger, and the fourth port of the four-way valve 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 flow 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 back to the compressor through the compressor's intake port to perform defrosting.

8. The outdoor unit of the air conditioner according to claim 1, characterized in that, The first spacing is 20 mm to 50 mm.

9. The outdoor unit of the air conditioner according to claim 1, characterized in that, The outdoor unit housing has a chassis, the chassis has a water tank and a drain hole, the drain hole connects the water tank and the outside of the outdoor unit housing, the outdoor heat exchanger is mounted on the chassis, and the lowest point of the heating device has a second distance from the lowest point of the water tank, the second distance being greater than or equal to 5 mm.

10. An air conditioner, characterized in that, include: An indoor unit, comprising an indoor heat exchanger and an indoor fan, is used to regulate indoor air. An outdoor unit, as described in any one of claims 1 to 9.

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