Heat exchanger blockage control method, device and air conditioner

Abstract

The present invention discloses a heat exchanger blockage control method, device, and air conditioner. The heat exchanger blockage control method includes: detecting the refrigerant pressure value in the heat exchanger outlet pipe, and determining that the heat exchanger is blocked when the refrigerant pressure value is greater than or equal to a first pressure threshold; detecting the current exhaust temperature and the air inlet and outlet temperatures of the heat exchanger, calculating the temperature difference between the air outlet temperature and the air inlet temperature, and calculating the blockage coefficient of the heat exchanger based on the current exhaust temperature and the temperature difference; performing frequency reduction control on the compressor to determine whether the blockage coefficient is greater than or equal to a preset coefficient threshold; and when the blockage coefficient is greater than or equal to the preset coefficient threshold, increasing the speed of the external fan until the external fan speed reaches a maximum speed. The present invention can predict the blockage of the heat exchanger, prevent the refrigerant pressure in the heat exchanger outlet pipe from continuing to rise, avoid frequent shutdowns of the air conditioner, and improve the stability of the air conditioner operation.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a method and device for controlling fouling and blockage of a heat exchanger, and an air conditioner. Background Art

[0002] The heat exchanger is a crucial heat exchange component in air conditioners. Currently, air conditioners typically use fin-and-tube heat exchangers. Due to the diverse fin types, complex structure, and small fin spacing, these heat exchangers are prone to becoming clogged after a period of use, impacting heat exchange performance. Existing heat exchanger clog control technologies typically shut down the air conditioner for protection when clogged heat exchangers are detected. This can lead to repeated shutdowns, increasing energy consumption, impacting normal air conditioner operation, and reducing operational stability. Summary of the Invention

[0003] To solve the above problems, the present invention provides a heat exchanger blockage control method, device and air conditioner, which can predict the blockage of the heat exchanger, alleviate the blockage of the heat exchanger and prevent the air conditioner from running with high energy consumption. At the same time, it can also prevent the refrigerant pressure in the heat exchanger outlet side pipeline from continuing to increase, avoid frequent shutdown of the air conditioner due to blockage of the heat exchanger, and improve the stability of the air conditioner operation.

[0004] According to an embodiment of the present invention, on the one hand, a method for controlling dirty blockage of a heat exchanger is provided, including: detecting the refrigerant pressure value in the outlet side pipeline of the heat exchanger, and determining that the heat exchanger is dirty and blocked when the refrigerant pressure value is greater than or equal to a first pressure threshold; detecting the current exhaust temperature and the inlet temperature and outlet temperature of the heat exchanger, calculating the temperature difference between the outlet temperature and the inlet temperature, and calculating the dirty blockage coefficient of the heat exchanger based on the current exhaust temperature and the temperature difference; performing frequency reduction control on the compressor to determine whether the dirty blockage coefficient is greater than or equal to a preset coefficient threshold; when the dirty blockage coefficient is greater than or equal to the preset coefficient threshold, performing speed increase control on the external fan speed until the external fan speed reaches the maximum speed.

[0005] By adopting the above technical solution, the dirty blockage coefficient of the heat exchanger is calculated based on the temperature difference between the outlet temperature and the inlet temperature and the exhaust temperature, so the dirty blockage of the heat exchanger can be predicted. By controlling the operating frequency of the compressor to reduce, the system pressure can be avoided from being shut down due to protection. By controlling the speed of the external fan to increase when the dirty blockage coefficient is large, the dirty blockage of the heat exchanger can be alleviated to prevent the air conditioner from running with high energy consumption. At the same time, it can also prevent the refrigerant pressure in the pipeline on the outlet side of the heat exchanger from continuing to increase, avoid frequent shutdowns of the air conditioner due to dirty blockage of the heat exchanger, and improve the stability of the air conditioner operation.

[0006] Preferably, the step of performing frequency reduction control on the compressor includes: controlling the compressor to operate at a first preset frequency; wherein the first preset frequency is greater than the minimum frequency of the compressor;

[0007] or,

[0008] The heat exchanger blockage control method is applied to an air conditioner, and a pressure switch is provided on the outlet pipe of the heat exchanger of the air conditioner. The pressure switch is disconnected when it detects that the refrigerant pressure value is greater than or equal to the first pressure threshold; the step of reducing the frequency of the compressor includes: controlling the compressor to reduce to the minimum frequency to close the pressure switch.

[0009] By adopting the above technical solution, the compressor is controlled to operate at a first preset frequency and the high-pressure pressure is reduced, which can avoid frequent protection shutdowns of the air conditioner and can also reduce the refrigerant pressure value in the heat exchanger outlet side pipeline for subsequent dirty blockage emergency control; by setting a pressure switch with a fixed disconnection threshold, it can be ensured that the heat exchanger has the same high-pressure temperature each time the dirty blockage coefficient is calculated, thereby improving the accuracy of dirty blockage prediction, and by controlling the compressor to operate at a minimum frequency to quickly reduce the high-pressure pressure, reduce the refrigerant pressure in the heat exchanger outlet side pipeline, and make the pressure switch close quickly to facilitate the next dirty blockage detection.

[0010] Preferably, the heat exchanger blockage control method further includes: when the pressure switch is closed, or when the pressure switch remains in the disconnected state after the compressor has been running at the minimum frequency for a first preset period of time, the compressor frequency increase rate is controlled until the frequency upper limit value is reached; wherein the frequency increase rate of the compressor is inversely correlated with the current operating frequency of the compressor.

[0011] By adopting the above technical solution, after the compressor frequency is reduced for a period of time, the compressor frequency is controlled to increase to ensure the capacity of the indoor unit, meet user needs, and improve user experience. By making the compressor frequency increase rate lower when the current operating frequency of the compressor is higher, the pressure is prevented from increasing too quickly and causing the pressure switch to disconnect again, thereby improving the reliability of the air conditioner operation.

[0012] Preferably, the step of controlling the frequency increase of the compressor includes: obtaining the operating frequency of the compressor when the pressure switch is disconnected, recorded as the first operating frequency Fn1; when the current operating frequency is ≤1 / 2*Fn1, controlling the frequency increase speed of the compressor to be a first frequency increase rate; when 1 / 2*Fn1<the current operating frequency ≤3 / 4*Fn1, controlling the frequency increase speed of the compressor to be a second frequency increase rate; when the current operating frequency is ≥3 / 4*Fn1, controlling the frequency increase speed of the compressor to be a third frequency increase rate; wherein, the first frequency increase rate>the second frequency increase rate>the third frequency increase rate.

[0013] By adopting the above technical solution, when the current operating frequency of the compressor is low, the compressor is controlled to increase the frequency at a normal frequency increase rate to ensure the output capacity of the indoor unit; when the operating frequency of the compressor is high, the frequency increase rate of the compressor is reduced to prevent the compressor from increasing the frequency too quickly and causing high-voltage lag, thereby improving the stability of the air conditioner operation; when the operating frequency of the compressor is close to the compressor frequency corresponding to the last time the pressure switch was disconnected, the compressor is controlled to increase the frequency slowly, while ensuring the cooling capacity of the indoor unit, preventing high-pressure overshoot and causing the pressure switch to be disconnected again, thereby improving the reliability of the heat exchanger blockage detection.

[0014] Preferably, it also includes: when the pressure switch is converted from an open state to a closed state, returning to execute the step of detecting the refrigerant pressure value in the outlet side pipeline of the heat exchanger, and when the pressure switch is disconnected again, determining that the heat exchanger is dirty and blocked; when the pressure switch is disconnected a number of times within a first preset time length, the frequency upper limit value of the compressor is corrected; wherein the corrected frequency upper limit value is Fn2-A; wherein Fn2 is the compressor operating frequency when the pressure switch was disconnected for the last time, and A is a constant.

[0015] By adopting the above technical solution, when the pressure switch is disconnected continuously for a large number of times, the frequency upper limit of the compressor is corrected to achieve emergency control of dirt and blockage of the air conditioner, and prevent the compressor from increasing the frequency again to the frequency when the pressure switch was disconnected last time when the capacity demand of the indoor unit increases or remains unchanged, thereby avoiding the disconnection of the pressure switch frequency and improving the stability of the air conditioner operation.

[0016] Preferably, the heat exchanger blockage control method further comprises: when the number of disconnections of the pressure switch within the first preset time reaches a preset number, calculating an average blockage coefficient of the heat exchanger, and displaying the blockage degree of the heat exchanger based on the average blockage coefficient;

[0017] and / or,

[0018] The dirty blocking coefficient or the average dirty blocking coefficient is transmitted to an indoor unit or a user terminal, and the dirty blocking coefficient or the average dirty blocking coefficient is displayed on the indoor unit or the user terminal to prompt a user to check the dirty blocking condition of the heat exchanger.

[0019] By adopting the above technical solution, after the dirty blocking coefficient or the average dirty blocking coefficient is calculated, the dirty blocking coefficient or the average dirty blocking coefficient of the heat exchanger is displayed based on the display screen of the indoor unit or the user terminal, so that the user can timely understand the dirty blocking degree of the heat exchanger and be prompted to check the dirty blocking condition of the outdoor heat exchanger.

[0020] Preferably, the calculation formula of the dirty and blocked coefficient is:

[0021] Ψ=1-(ΔT1 / ΔT)×η

[0022] η=(Ta / Ti1)×η1×(Td1 / Td)×η2

[0023] Among them, Ψ is the dirty blockage coefficient, ΔT1 is the temperature difference, ΔT is the preset standard temperature difference, Td1 is the current exhaust temperature, Td is the preset standard exhaust temperature, Ta is the preset standard outer ring temperature, η1 is the outer ring temperature correction coefficient, and η2 is the exhaust temperature correction coefficient.

[0024] By adopting the above technical solution, the relationship between the temperature difference between the air outlet and the air inlet of the heat exchanger and the standard temperature difference, the influence of the outer ring temperature and the exhaust temperature are taken into consideration, so that the calculated dirty blockage coefficient is more accurate.

[0025] Preferably, the step of controlling the external fan speed to increase the speed until the external fan speed reaches the maximum speed includes: controlling the external fan windshield to increase the preset gear position until the external fan windshield reaches the highest windshield.

[0026] By adopting the above technical solution and controlling the outdoor fan damper to rise to a preset gear, the heat exchanger can be guaranteed to meet the needs of the indoor unit, thereby improving the reliability of the air conditioner operation and enhancing the user experience.

[0027] According to an embodiment of the present invention, on the other hand, a dirty blockage control device for a heat exchanger is provided, including: a first detection module, used to detect the refrigerant pressure value in the outlet side pipeline of the heat exchanger, and when the refrigerant pressure value is greater than or equal to a first pressure threshold, it is determined that the heat exchanger is dirty and blocked; a second detection module, used to detect the current exhaust temperature and the inlet temperature and outlet temperature of the heat exchanger, calculate the temperature difference between the outlet temperature and the inlet temperature, and calculate the dirty blockage coefficient of the heat exchanger based on the current exhaust temperature and the temperature difference; a first control module, used to perform frequency reduction control on the compressor, and determine whether the dirty blockage coefficient is greater than or equal to a preset coefficient threshold; a second control module, used to increase the speed of the external fan when the dirty blockage coefficient is greater than or equal to the preset coefficient threshold, until the external fan speed reaches the maximum speed.

[0028] According to an embodiment of the present invention, on the other hand, an air conditioner is provided, comprising a computer-readable storage medium storing a computer program and a processor, wherein the outlet pipe of the heat exchanger of the air conditioner is provided with a pressure switch, and the pressure switch is disconnected when it detects that the refrigerant pressure value is greater than the first pressure threshold value, and when the computer program is read and executed by the processor, the method described in any one of the first aspects is implemented.

[0029] The present invention has the following beneficial effects: by calculating the dirty blockage coefficient of the heat exchanger according to the temperature difference between the air outlet temperature and the air inlet temperature and the exhaust temperature when dirty blockage is detected on the surface of the heat exchanger, the dirty blockage situation of the heat exchanger can be predicted, and by controlling the operating frequency of the compressor to reduce, the system pressure can be avoided from being shut down due to protection by excessive pressure; by controlling the speed of the external fan to increase when the dirty blockage coefficient is large, the dirty blockage situation of the heat exchanger can be alleviated to prevent the air conditioner from running with high energy consumption; at the same time, the refrigerant pressure in the outlet side pipeline of the heat exchanger can be prevented from continuing to increase, thereby avoiding frequent shutdowns of the air conditioner due to dirty blockage of the heat exchanger, and improving the stability of the air conditioner operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other implementation drawings based on the provided drawings without inventive effort.

[0031] The structures, proportions, sizes, etc. illustrated in this specification are intended only to complement the contents disclosed herein and to facilitate understanding and reading by persons familiar with the art. They are not intended to limit the conditions under which the present invention may be implemented and therefore have no substantive technical significance. Any structural modifications, changes in proportions, or adjustments in sizes, without affecting the efficacy and objectives of the present invention, shall still fall within the scope of the technical contents disclosed herein.

[0032] Figure 1 A flow chart of a heat exchanger fouling control method provided by the present invention;

[0033] Figure 2 A schematic structural diagram of an air conditioner provided by the present invention;

[0034] Figure 3 This is a structural schematic diagram of a heat exchanger fouling control device provided by the present invention. DETAILED DESCRIPTION

[0035] The following describes the implementation of the present invention using specific embodiments. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. Obviously, the embodiments described are only a portion of the present invention, not all of it. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0037] This embodiment provides a heat exchanger fouling control method, which can be applied to air conditioners. Figure 1 The flow chart of the heat exchanger fouling control method shown in FIG. 1 mainly includes the following steps S102 to S108:

[0038] Step S102: detecting the refrigerant pressure value in the outlet pipe of the heat exchanger. When the refrigerant pressure value is greater than or equal to a first pressure threshold, determining that the heat exchanger is dirty or blocked.

[0039] A pressure sensor or pressure switch is provided on the pipeline on the outlet side of the heat exchanger (i.e., the coil outlet side) to detect whether the refrigerant pressure value in the pipeline on the outlet side of the heat exchanger has reached a first pressure threshold. During the cooling operation of the air conditioner, when the heat exchanger is clogged, the refrigerant dissipates heat poorly, and the refrigerant pressure of the heat exchanger will also increase. The first pressure threshold can be the refrigerant pressure range in the heat exchanger when the heat exchanger is clogged to a certain extent. For example, the value range of the first pressure threshold can be 2.8 to 3.5 MPa. When the refrigerant pressure value in the pipeline on the outlet side of the heat exchanger is detected to be greater than the first pressure threshold, it indicates that the heat exchanger surface is clogged.

[0040] Step S104: Detect the current exhaust temperature and the inlet and outlet temperatures of the heat exchanger, calculate the temperature difference between the outlet and inlet temperatures, and calculate the fouling coefficient of the heat exchanger based on the current exhaust temperature and the temperature difference.

[0041] When the pressure sensor detects that the refrigerant pressure exceeds a first pressure threshold, or when a pressure switch on the heat exchanger outlet pipe operates, the system records the current exhaust temperature Td1, the outdoor heat exchanger's outlet temperature To1, and the inlet temperature Ti1. The temperature difference between the outlet and inlet temperatures, ΔT1 = To1 - Ti1, is calculated. This temperature difference is then compared with the standard temperature difference ΔT between the outlet and inlet temperatures when the heat exchanger is not clogged, to estimate the degree of heat exchanger clog. The system also considers the impact of outdoor ambient temperature on compressor exhaust temperature: higher outdoor ambient temperature reduces heat exchanger efficiency, increases compressor exhaust temperature, increases refrigerant-side temperature, and correspondingly increases the air-side heat exchange temperature difference. By estimating the heat exchanger's clog coefficient based on the outlet and inlet temperature difference and the current exhaust temperature, the estimated clog degree is more accurate. A larger clog coefficient indicates more severe heat exchanger clogs, while a smaller clog coefficient indicates less clogged heat exchanger surfaces.

[0042] In a specific embodiment, the calculation formula of the dirty and blocked coefficient is:

[0043] Ψ=1-(ΔT1 / ΔT)×η

[0044] η=(Ta / Ti1)×η1×(Td1 / Td)×η2

[0045] Where Ψ is the dirty blockage coefficient, ΔT1 is the temperature difference, ΔT is the preset standard temperature difference, Td1 is the current exhaust temperature, Td is the preset standard exhaust temperature, Ta is the preset standard outer ring temperature, η1 is the outer ring temperature correction coefficient, and η2 is the exhaust temperature correction coefficient. The value range of Td is 70-90°C; the value range of Ta is 32-38°C, preferably 35°C; the value range of ΔT is 10-15°C; the value range of η1 is 1-2, and the value range of η2 is 0.4-0.8.

[0046] Step S106: performing frequency reduction control on the compressor to determine whether the dirty and clogging coefficient is greater than or equal to a preset coefficient threshold.

[0047] After calculating the dirty and clogging coefficient, the frequency of the compressor is controlled to be reduced. By controlling the compressor to reduce the frequency, the high pressure of the system can be reduced to avoid the air conditioner protection shutdown. At the same time, the refrigerant pressure in the heat exchanger outlet side pipeline can be reduced to ensure the stable operation of the air conditioner.

[0048] Step S108: When the dirt and blockage coefficient is greater than or equal to the preset coefficient threshold, the speed of the external fan is increased until the speed of the external fan reaches the maximum speed.

[0049] The dirtiness and clogging coefficient can range from 0 to 1, and the preset coefficient threshold can range from 0.4 to 0.7, with a preferred value of 0.5. When the dirtiness and clogging coefficient of the heat exchanger is greater than or equal to the preset coefficient threshold, it indicates that the heat exchanger is highly dirty and clogged. By increasing the speed of the outdoor fan to increase the air volume, the heat exchanger's heat transfer capacity can be guaranteed, thereby improving the indoor unit's performance. At the same time, a high air volume can be used to blow away dust on the surface of the heat exchanger, reducing the degree of dirtiness and clogging of the heat exchanger and preventing the air conditioner from operating in a state of high energy consumption.

[0050] In a specific embodiment, the external fan damper can be controlled to increase the preset gear until the external fan damper reaches the highest wind speed. When the dirt blockage coefficient is greater than or equal to the preset coefficient threshold, the external fan speed is corrected, and the external fan is controlled to increase the preset gear based on the current wind speed. The value range of the preset gear can be 1 to 2 levels. For example, if the current wind speed of the external fan is level 3, the external fan is controlled to increase to level 4 wind speed and operate until the external fan reaches the highest allowed wind speed, and the control of the external fan to increase the wind speed is stopped. By controlling the external fan damper to increase the preset gear, the heat exchanger of the heat exchanger can be guaranteed to meet the needs of the indoor unit, thereby improving the reliability of the air conditioner operation and improving the user experience.

[0051] When the dirt and blockage coefficient of the heat exchanger is less than the above-mentioned preset coefficient threshold, it indicates that the dirt and blockage degree of the heat exchanger surface is relatively small, and the air conditioner maintains normal operation to save air conditioning energy consumption.

[0052] The above-mentioned heat exchanger blockage control method provided in this embodiment can predict the blockage of the heat exchanger by calculating the blockage coefficient of the heat exchanger based on the temperature difference between the outlet temperature and the inlet temperature and the exhaust temperature when blockage is detected on the surface of the heat exchanger. By controlling the operating frequency of the compressor to reduce, the system pressure can be prevented from being shut down due to protection. By controlling the speed of the external fan to increase when the blockage coefficient is large, the blockage of the heat exchanger can be alleviated to prevent the air conditioner from running at a high energy consumption. At the same time, it can also prevent the refrigerant pressure in the outlet side pipeline of the heat exchanger from continuing to increase, avoid frequent shutdowns of the air conditioner due to blockage of the heat exchanger, and improve the stability of the air conditioner operation.

[0053] In one embodiment, this embodiment provides two implementation methods for frequency reduction control of the compressor, which can be specifically implemented with reference to the following implementation methods 1 and 2:

[0054] Embodiment 1: In this embodiment, a pressure sensor is installed on the heat exchanger outlet pipeline. When the refrigerant pressure detected by the pressure sensor is greater than a first pressure threshold and the dirt and blockage coefficient is calculated, the compressor is controlled to operate at a first preset frequency. The first preset frequency may be greater than the compressor's minimum frequency. By controlling the compressor to operate at the first preset frequency, the high-pressure pressure is reduced, thereby avoiding frequent protective shutdowns of the air conditioner and reducing the refrigerant pressure in the heat exchanger outlet pipeline to facilitate subsequent dirt and blockage emergency control.

[0055] Embodiment 2: In this embodiment, a pressure switch is provided on the outlet pipe of the heat exchanger of the air conditioner. The pressure switch is disconnected when it detects that the refrigerant pressure value is greater than a first pressure threshold. The compressor is controlled to reduce its operating frequency to close the pressure switch.

[0056] See for example Figure 2 The air conditioner structure diagram shown in FIG. 1 includes a compressor 21, a pipeline 22, a four-way valve 23, an air outlet temperature sensor 24, an outdoor fan 25, an air inlet temperature sensor 26, a heat exchanger 27, a pressure switch 28, a throttling device 29, and an indoor unit 20. The pressure switch 28 is provided on the pipeline at the outlet side of the outdoor heat exchanger 27.

[0057] The pressure switch can be a normally closed pressure switch, closed when the refrigerant pressure is less than a first pressure threshold, and open when the refrigerant pressure is greater than or equal to the first pressure threshold. By providing a pressure switch with a fixed disconnection threshold at the heat exchanger outlet, the heat exchanger maintains the same high-pressure temperature each time the dirty blockage coefficient is calculated, improving the accuracy of dirty blockage prediction. By controlling the compressor to operate at a minimum frequency to rapidly reduce the high-pressure pressure, the refrigerant pressure in the heat exchanger outlet pipeline is reduced, allowing the pressure switch to close quickly to facilitate the next dirty blockage detection.

[0058] In one embodiment, the method provided in this embodiment also includes: when the pressure switch is closed, or when the pressure switch is continuously in the disconnected state after the compressor runs at the minimum frequency for a first preset period of time, the frequency increase rate of the compressor is controlled until the frequency upper limit value is reached; wherein the frequency increase rate of the compressor is inversely correlated with the current operating frequency of the compressor.

[0059] The value range of the above-mentioned first preset time can be 5 to 10 minutes. When the pressure switch is detected to be closed, or the compressor continues to run at the minimum frequency for the first preset time t1 and the pressure switch is continuously in the disconnected state, in order to ensure the capacity of the indoor unit, the compressor is allowed to run at an increased frequency and the compressor is slowly controlled to increase its frequency.

[0060] By controlling the compressor frequency to increase after the compressor frequency has been reduced for a period of time, the capacity of the indoor unit is guaranteed, user needs are met, and the user experience is improved. By making the compressor frequency increase rate lower when the current operating frequency of the compressor is higher, the pressure is prevented from increasing too quickly and causing the pressure switch to disconnect again, thereby improving the reliability of the air conditioner operation.

[0061] In one embodiment, to ensure the capacity of the indoor unit, this embodiment provides an implementation method for controlling the frequency increase of the compressor, which can be specifically performed with reference to the following steps:

[0062] Step (1): Obtain the compressor operating frequency when the pressure switch is disconnected, and record it as the first operating frequency Fn1.

[0063] The compressor operating frequency detected when the pressure switch is most recently disconnected is obtained and recorded as the first operating frequency Fn1.

[0064] Step (2): If the current operating frequency is ≤ 1 / 2*Fn1, the frequency increase speed of the compressor is controlled to be the first frequency increase speed.

[0065] The first frequency increase rate mentioned above is the normal frequency increase rate of the compressor. If the current operating frequency of the compressor is ≤1 / 2*Fn1, it indicates that the frequency difference between the compressor and the pressure switch when they are disconnected is large. When the compressor operates at a low frequency, the high pressure is low. The compressor can increase the frequency at the normal frequency increase rate to ensure the capacity output of the indoor unit.

[0066] Step (3): When 1 / 2*Fn1<current operating frequency≤3 / 4*Fn1, control the frequency increase speed of the compressor to be the second frequency increase speed.

[0067] The second frequency increase rate is lower than the first frequency increase rate. The second frequency increase rate can range from normal frequency increase rate * 0.4 to normal frequency increase rate * 0.6, with a preferred value of normal frequency increase rate * 0.5. When 1 / 2 * Fn1 < current operating frequency ≤ 3 / 4 * Fn1, the compressor's operating frequency is too high. By reducing the compressor's frequency increase rate, high-voltage hysteresis caused by excessive frequency increase is prevented, thereby improving the stability of the air conditioner's operation.

[0068] Step (4): If the current operating frequency is ≥3 / 4*Fn1, the frequency increase speed of the compressor is controlled to be the third frequency increase speed.

[0069] The first frequency increase rate is greater than the second frequency increase rate and greater than the third frequency increase rate. The third frequency increase rate can range from normal frequency increase rate * 0.2 to normal frequency increase rate * 0.3, with a preferred value of normal frequency increase rate * 0.25. If the current operating frequency is ≥ 3 / 4 * Fn1, this indicates that the compressor's operating frequency is close to the compressor frequency corresponding to the last time the pressure switch disconnected. This controls the compressor to slowly increase its frequency, ensuring the indoor unit's cooling capacity while preventing high-pressure overshoot that could cause the pressure switch to disconnect again, thereby improving the reliability of heat exchanger blockage detection.

[0070] In one embodiment, the method provided in this embodiment also includes: when the pressure switch is converted from an open state to a closed state, returning to execute the above step S102 to detect the state of the pressure switch again; when the pressure switch is disconnected again, determining that the heat exchanger is dirty and blocked, calculating the dirty and blocked coefficient of the heat exchanger again, and controlling the compressor and the outdoor fan to ensure normal operation of the air conditioner.

[0071] When the pressure switch is disconnected a preset number of times within the first preset time period, the frequency upper limit value of the compressor is corrected; wherein the corrected frequency upper limit value is Fn2-A; wherein Fn2 is the operating frequency of the compressor when the pressure switch is most recently disconnected, A is a constant, and the value range of A can be 2 to 10 Hz.

[0072] The first preset duration may be in the range of 30 to 60 minutes, and the preset number of times may be in the range of 3 or more, with a preferred value of 3. When the pressure switch is disconnected more than or equal to the preset number of times within the first preset duration, it indicates that the heat exchanger surface is severely clogged. The compressor frequency upper limit is corrected to achieve emergency control of the air conditioner's clogged condition, preventing the compressor from increasing its frequency again to the frequency at which the pressure switch was previously disconnected when the indoor unit's capacity demand increases or remains unchanged, thereby avoiding the pressure switch frequency disconnection and improving the stability of the air conditioner's operation.

[0073] In one embodiment, the method provided in this embodiment further includes: when the pressure switch is disconnected a preset number of times within the first preset time, calculating the average dirty blocking coefficient of the heat exchanger, and displaying the degree of dirty blocking of the heat exchanger based on the average dirty blocking coefficient.

[0074] For example, when the pressure switch is detected to be disconnected three times within the first preset time period, the dirty blocking coefficient calculated each time the pressure switch is disconnected is obtained, and the average value of the three dirty blocking coefficients is calculated. The average dirty blocking coefficient can more accurately reflect the degree of dirty blocking of the heat exchanger, that is, Ψ = (Ψ1 + Ψ2 + Ψ3) / 3, which improves the calculation accuracy of the dirty blocking coefficient.

[0075] In one embodiment, the method provided in this embodiment also includes: transmitting the dirty blocking coefficient or the average dirty blocking coefficient to the indoor unit or the user terminal, and displaying the dirty blocking coefficient or the average dirty blocking coefficient based on the indoor unit or the user terminal to prompt the user to check the dirty blocking condition of the heat exchanger.

[0076] After the dirty blocking coefficient or average dirty blocking coefficient is calculated, the dirty blocking coefficient or average dirty blocking coefficient of the heat exchanger is displayed on the display screen of the indoor unit or the user terminal, so that the user can timely understand the dirty blocking degree of the heat exchanger and be prompted to check the dirty blocking condition of the outdoor heat exchanger.

[0077] In one embodiment, when the pressure switch is detected to be in a closed state for a continuous first preset time period, or the air conditioner changes the operating mode, or the air conditioner restarts, the control of the external fan speed is stopped, the control of the compressor frequency increase is stopped, and the emergency control of the compressor is stopped.

[0078] The method for controlling the fouling and blockage of the heat exchanger provided in this embodiment can determine the refrigerant pressure state by using a pressure switch on the outlet side of the heat exchanger and detecting the state of the pressure switch. It can predict the fouling and blockage of the heat exchanger by calculating the fouling and blockage coefficient based on the temperature difference between the air inlet and the air outlet of the heat exchanger. It can prevent the high pressure from continuing to rise by adjusting the compressor and the external fan after the pressure switch is disconnected. It can also correct the frequency upper limit of the compressor and the fan speed when the pressure switch is repeatedly operated, thereby increasing emergency operation and ensuring the normal use of the air conditioner.

[0079] Corresponding to the heat exchanger blockage control method provided in the above embodiment, the present invention provides an example of applying the above blockage control method to predict blockage and perform emergency control on an air conditioning heat exchanger. The heat exchanger is provided with temperature sensors at the air inlet and outlet, and a pressure switch is provided on the outlet pipe of the heat exchanger. Taking the outdoor heat exchanger of a refrigeration cycle as an example, the following steps can be specifically performed:

[0080] Step 1: While the air conditioner is running, check the status of the pressure switch (using a normally closed pressure switch as an example: it closes when the refrigerant pressure is below the first threshold and opens when the pressure is above the second threshold). If the heat exchanger becomes clogged, the refrigerant will not dissipate heat properly, and the refrigerant pressure in the heat exchanger will increase. If the pressure switch is closed, the air conditioning system will continue to regulate and control normally.

[0081] In step 2, when the pressure switch is detected to be disconnected (preferably between 2.8 and 3.5 MPa), the heat exchanger pressure has reached the preset threshold and the heat exchanger surface is clogged. The compressor frequency Fn1, the outdoor fan damper r1, the exhaust temperature Td1, and the outdoor heat exchanger inlet and outlet temperatures Ti1 and To1 are recorded at the moment the pressure switch is disconnected. The pressure switch disconnects at a fixed pressure threshold. Presetting a fixed pressure switch value ensures the same high-pressure temperature across the heat exchanger during each calculation, improving the accuracy of clog prediction.

[0082] In step 3, when the heat exchanger surface is clogged, its heat transfer rate is directly affected. Based on the positive relationship between heat transfer rate and temperature difference, the difference between the inlet and outlet temperatures on the air side of the heat exchanger is used to estimate the degree of clogged heat exchanger surface. First, the temperature difference between the two sides of the heat exchanger is calculated as ΔT1 = To1 - Ti1. Then, the standard temperature difference ΔT when the heat exchanger is not clogged is compared. The influence of the outer ring temperature and the compressor exhaust temperature is taken into account. That is, under the same conditions, when the outer ring temperature increases, the heat transfer efficiency decreases and the temperature difference decreases. When the exhaust temperature increases, the temperature increase on the refrigerant side will correspondingly increase the heat transfer temperature difference on the air side. Therefore, the outer ring temperature correction coefficient η1 and the exhaust temperature correction coefficient η2 are increased to make the estimate more accurate.

[0083] Calculate the dirty blockage coefficient of the condenser according to the following formula:

[0084] Ψ=1-(ΔT1 / ΔT)×η

[0085] η=(Ta / Ti1)×η1×(Td1 / Td)×η2

[0086] Wherein: Ψ is the dirty blocking coefficient. A large dirty blocking coefficient indicates that the heat exchanger is seriously blocked. Conversely, a small dirty blocking coefficient indicates that the heat exchanger is less blocked. ΔT is the preset standard temperature difference, which is determined according to the structural form of the heat exchanger, preferably 10-15°C. Td is the preset standard exhaust temperature, and Ta is the preset standard outer ring temperature. Ta is preferably 35°C under rated operating conditions, and Td is preferably 70-90°C. η1 and η2 are respectively the outer ring correction coefficient and the exhaust correction coefficient. η1 is preferably 1-2, and η2 is preferably 0.4-0.8.

[0087] In step 4, after calculating the fouling coefficient, the compressor is controlled to reduce its frequency to the minimum allowable frequency. Since the pressure switch is open at this point, the compressor frequency is reduced to close the pressure switch for the next fouling detection. This reduces the high-pressure pressure and allows the pressure switch to close quickly. The compressor is allowed to increase its frequency after operating at the minimum frequency for a period of time t1 (preferably 5-10 minutes) or after the pressure switch is detected to be closed. The fouling coefficient is simultaneously transmitted via an electrical signal to the indoor unit display or directly pushed to the user, prompting them to check for fouling in the outdoor heat exchanger.

[0088] In step 5, after calculating the fouling coefficient, if the fouling coefficient Ψ ≥ 0.5, the fan speed is adjusted to increase the fan speed by one level above the current wind speed. For example, if the current wind speed r is level 3, the fan is operated at level 4 until the fan wind speed reaches the highest allowable level. This increases the air volume to ensure heat exchange through the heat exchanger and improves the indoor unit's performance. If the fouling coefficient Ψ is less than 0.5, indicating minimal fouling, maintain normal control for energy conservation.

[0089] Step 6: After the compressor drops to the minimum frequency allowed in step 4 above, if the pressure switch remains in the disconnected state after the running time t1, to ensure the capacity of the indoor unit, the following slow frequency increase control is entered:

[0090] When the current operating frequency of the compressor Fn≤1 / 2*Fn1, the frequency increase rate of the compressor is controlled to be the normal frequency increase rate. When the compressor runs at a low frequency, the high pressure is low. Normal frequency increase adjustment is conducive to ensuring the output capacity.

[0091] When 1 / 2*Fn1<Fn≤3 / 4*Fn1, the compressor frequency increase rate is 1 / 2 of the normal frequency increase rate, which prevents the compressor frequency from increasing too quickly and causing high-pressure hysteresis, thereby improving the system operation stability;

[0092] When Fn≥3 / 4*Fn1, the compressor frequency increase rate is 1 / 4 of the normal frequency increase rate, controlling the compressor to increase the frequency slowly, ensuring the cooling capacity of the indoor unit while preventing the high-pressure overshoot from causing the pressure switch to disconnect again.

[0093] Step 7: If the pressure switch is detected to be disconnected ≥ n times (n is preferably 3) within a continuous time t2 (preferably 30 to 60 minutes), it indicates that the heat exchanger is seriously blocked. The blockage coefficient is calculated three times and the average is taken, i.e., Ψ = (Ψ1 + Ψ2 + Ψ3) / 3, to increase the accuracy of the calculation.

[0094] At the same time, in order to increase the stability of system operation, enter the following emergency control:

[0095] The compressor frequency upper limit is corrected to Fn2-A (A is preferably 2-10 Hz), where Fn2 is the compressor frequency detected when the pressure switch last tripped. This prevents the compressor from increasing to the frequency of the previous pressure switch trip when the indoor unit's power demand increases or remains unchanged, which could cause the pressure switch to trip frequently, thereby improving air conditioner operation stability.

[0096] Step 8: When it is detected that the pressure switch is closed continuously for the continuous time t2, or the air conditioner switches the operating mode, or the air conditioner is restarted, the above-mentioned outdoor fan damper correction, compressor slow frequency increase control and compressor emergency control are canceled.

[0097] The heat exchanger blockage prediction and emergency control method provided in this embodiment predicts heat exchanger blockage by using a pressure switch and a temperature sensor, thereby promptly detecting heat exchanger blockage, avoiding safety hazards, preventing high energy consumption of the air conditioner, increasing emergency control, and preventing frequent shutdowns of the air conditioner due to heat exchanger blockage, thereby ensuring stable and reliable operation of the air conditioner and increasing the service life and comfort of the air conditioner.

[0098] Corresponding to the heat exchanger fouling control method provided in the above embodiment, the present invention provides a heat exchanger fouling control device, which can be applied to air conditioners, see Figure 3 The heat exchanger fouling control device shown in the figure is a schematic diagram of the structure, which includes the following modules:

[0099] The first detection module 31 is used to detect the refrigerant pressure value in the outlet pipe of the heat exchanger. When the refrigerant pressure value is greater than a first pressure threshold, it is determined that the heat exchanger is dirty or blocked.

[0100] The second detection module 32 is used to detect the current exhaust temperature and the inlet and outlet temperatures of the heat exchanger, calculate the temperature difference between the outlet and inlet temperatures, and calculate the dirty and blocking coefficient of the heat exchanger based on the current exhaust temperature and the temperature difference;

[0101] The first control module 33 is used to perform frequency reduction control on the compressor and determine whether the dirty and blocking coefficient is greater than or equal to a preset coefficient threshold;

[0102] The second control module 34 is configured to control the speed of the external fan to increase when the dirt and blockage coefficient is greater than or equal to a preset coefficient threshold, until the speed of the external fan reaches a maximum speed.

[0103] The heat exchanger blockage control device provided in this embodiment can predict the blockage of the heat exchanger by calculating the blockage coefficient of the heat exchanger based on the temperature difference between the outlet temperature and the inlet temperature and the exhaust temperature when blockage is detected on the surface of the heat exchanger. It can avoid the system pressure being too high and shutting down due to protection by controlling the operating frequency of the compressor to decrease. It can alleviate the blockage of the heat exchanger by controlling the speed of the external fan to increase when the blockage coefficient is large, and prevent the air conditioner from running at high energy consumption. At the same time, it can also prevent the refrigerant pressure in the outlet side pipeline of the heat exchanger from continuing to increase, avoid frequent shutdowns of the air conditioner due to blockage of the heat exchanger, and improve the stability of the air conditioner operation.

[0104] In one embodiment, the first control module 33 is configured to control the compressor to operate at a first preset frequency; wherein the first preset frequency is greater than the minimum frequency of the compressor.

[0105] In one embodiment, a pressure switch is provided on the outlet side pipeline of the heat exchanger of the air conditioner, and the pressure switch is disconnected when it detects that the refrigerant pressure value is greater than or equal to the first pressure threshold; the first control module 33 is used to control the compressor to reduce the operation to the minimum frequency so that the pressure switch is closed.

[0106] In one embodiment, the above device further comprises:

[0107] The frequency increase module is used to control the frequency increase of the compressor until the frequency upper limit value is reached when the pressure switch is closed or when the pressure switch is continuously in the open state after the compressor has been running at the minimum frequency for a first preset period of time; wherein the frequency increase rate of the compressor is inversely correlated with the current operating frequency of the compressor.

[0108] In one embodiment, the above-mentioned frequency increase module is used to obtain the operating frequency of the compressor when the pressure switch is disconnected, which is recorded as the first operating frequency Fn1; when the current operating frequency is ≤1 / 2*Fn1, the frequency increase speed of the compressor is controlled to be the first frequency increase rate; when 1 / 2*Fn1<current operating frequency ≤3 / 4*Fn1, the frequency increase speed of the compressor is controlled to be the second frequency increase rate; when the current operating frequency is ≥3 / 4*Fn1, the frequency increase speed of the compressor is controlled to be the third frequency increase rate; wherein, the first frequency increase rate>the second frequency increase rate>the third frequency increase rate.

[0109] In one embodiment, the above device further comprises:

[0110] The correction module is used to correct the frequency upper limit value of the compressor when the number of disconnections of the pressure switch reaches a preset number within a first preset time period; wherein the corrected frequency upper limit value is Fn2-A; wherein Fn2 is the compressor operating frequency when the pressure switch is most recently disconnected, and A is a constant.

[0111] a display module configured to calculate an average dirty and blocking coefficient of the heat exchanger when the pressure switch is disconnected a preset number of times within a first preset time period, and to display a degree of dirty and blocking of the heat exchanger based on the average dirty and blocking coefficient;

[0112] The prompt module is used to transmit the dirty blocking coefficient or the average dirty blocking coefficient to the indoor unit or the user terminal, and display the dirty blocking coefficient or the average dirty blocking coefficient based on the indoor unit or the user terminal to prompt the user to check the dirty blocking condition of the heat exchanger.

[0113] In one embodiment, the calculation formula of the dirty and blocked coefficient is:

[0114] Ψ=1-(ΔT1 / ΔT)×η

[0115] η=(Ta / Ti1)×η1×(Td1 / Td)×η2

[0116] Among them, Ψ is the dirty blockage coefficient, ΔT1 is the temperature difference, ΔT is the preset standard temperature difference, Td1 is the current exhaust temperature, Td is the preset standard exhaust temperature, Ta is the preset standard outer loop temperature, η1 is the outer loop temperature correction coefficient, and η2 is the exhaust temperature correction coefficient.

[0117] In one embodiment, the second control module 34 is configured to control the external fan windshield to rise to a preset gear position until the external fan windshield reaches the highest windshield.

[0118] The blockage control device for the heat exchanger provided in this embodiment can determine the refrigerant pressure state by using a pressure switch on the outlet side of the heat exchanger and detecting the state of the pressure switch. It can predict the blockage condition of the heat exchanger by calculating the blockage coefficient based on the temperature difference between the air inlet and the air outlet of the heat exchanger. It can prevent the high pressure from continuing to rise by adjusting the compressor and the external fan after the pressure switch is disconnected. It can also correct the frequency upper limit of the compressor and the fan speed when the pressure switch is repeatedly operated, thereby increasing emergency operation and ensuring the normal use of the air conditioner.

[0119] Corresponding to the heat exchanger blockage control method provided in the above embodiment, this embodiment provides an air conditioner, which includes a computer-readable storage medium storing a computer program and a processor. The outlet pipe of the heat exchanger of the air conditioner is provided with a pressure switch, and the pressure switch is disconnected when it detects that the refrigerant pressure value is greater than the first pressure threshold. When the computer program is read and run by the processor, the heat exchanger blockage control method provided in the above embodiment is implemented.

[0120] This embodiment also provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the various processes of the heat exchanger fouling control method embodiment described above, achieving the same technical effects. To avoid repetition, the details are omitted here. The computer-readable storage medium may be, for example, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0121] Of course, those skilled in the art will understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the control device through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it may include the processes of the above-mentioned method embodiments, wherein the storage medium may be a memory, a disk, an optical disk, etc.

[0122] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

[0123] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0124] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between the various embodiments can be referred to in conjunction with each other. The heat exchanger fouling control device and air conditioner disclosed in the embodiments correspond to the heat exchanger fouling control method disclosed in the embodiments, so the description is relatively simple. For relevant details, refer to the method description.

[0125] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

[0126] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A method for controlling fouling and blockage of a heat exchanger, characterized in that: include: Detecting a refrigerant pressure value in a pipeline on an outlet side of the heat exchanger, and determining that the heat exchanger is clogged when the refrigerant pressure value is greater than or equal to a first pressure threshold; detecting a current exhaust temperature and an air inlet temperature and an air outlet temperature of the heat exchanger, calculating a temperature difference between the air outlet temperature and the air inlet temperature, and calculating a fouling coefficient of the heat exchanger based on the current exhaust temperature and the temperature difference; Performing frequency reduction control on the compressor to determine whether the dirty and clogging coefficient is greater than or equal to a preset coefficient threshold; When the dirt and blockage coefficient is greater than or equal to the preset coefficient threshold, the speed of the external fan is increased until the speed of the external fan reaches the maximum speed; The calculation formula of the dirty blocking coefficient is: Ψ=1-(ΔT1 / ΔT)×η η=(Ta / Ti1)×η1×(Td1 / Td)×η2 Among them, Ψ is the dirty blockage coefficient, ΔT1 is the temperature difference, ΔT is the preset standard temperature difference, Td1 is the current exhaust temperature, Td is the preset standard exhaust temperature, Ta is the preset standard outer ring temperature, η1 is the outer ring temperature correction coefficient, η2 is the exhaust temperature correction coefficient, and Ti1 is the air inlet temperature.

2. The heat exchanger fouling control method according to claim 1, characterized in that: The step of performing frequency reduction control on the compressor includes: Controlling the compressor to operate at a first preset frequency; wherein the first preset frequency is greater than the minimum frequency of the compressor; or, The heat exchanger blockage control method is applied to an air conditioner, wherein a pressure switch is provided on an outlet pipe of the heat exchanger of the air conditioner, and the pressure switch is disconnected when it detects that the refrigerant pressure value is greater than or equal to the first pressure threshold; the step of reducing the frequency of the compressor includes: The compressor is controlled to reduce its operation frequency to the minimum frequency so that the pressure switch is closed.

3. The heat exchanger fouling control method according to claim 2, characterized in that: Also includes: When the pressure switch is closed, or when the pressure switch remains in the open state after the compressor operates at the minimum frequency for a first preset period of time, the frequency increase rate of the compressor is controlled until the frequency upper limit is reached; wherein the frequency increase rate of the compressor is inversely correlated with the current operating frequency of the compressor.

4. The heat exchanger fouling control method according to claim 3, characterized in that: The step of controlling the frequency increase of the compressor includes: Obtaining the operating frequency of the compressor when the pressure switch is disconnected, recorded as a first operating frequency Fn1; When the current operating frequency is ≤ 1 / 2*Fn1, controlling the frequency increase speed of the compressor to be a first frequency increase speed; When 1 / 2*Fn1<the current operating frequency≤3 / 4*Fn1, controlling the frequency increase speed of the compressor to be the second frequency increase speed; When the current operating frequency is ≥3 / 4*Fn1, the frequency increase speed of the compressor is controlled to be a third frequency increase speed; wherein the first frequency increase speed>the second frequency increase speed>the third frequency increase speed.

5. The heat exchanger fouling control method according to claim 2, characterized in that: Also includes: When the pressure switch is switched from an open state to a closed state, returning to the step of detecting the refrigerant pressure value in the outlet pipe of the heat exchanger, and when the pressure switch is opened again, determining that the heat exchanger is blocked by dirt; When the pressure switch is disconnected a preset number of times within the first preset time period, the frequency upper limit value of the compressor is corrected; wherein the corrected frequency upper limit value is Fn2-A; wherein Fn2 is the compressor operating frequency when the pressure switch was disconnected the most recently, and A is a constant.

6. The heat exchanger fouling control method according to claim 5, characterized in that: Also includes: When the pressure switch is disconnected a number of times within a first preset time period reaches a preset number, an average dirty and blocking coefficient of the heat exchanger is calculated, and a dirty and blocking degree of the heat exchanger is displayed based on the average dirty and blocking coefficient; and / or, The dirty blocking coefficient or the average dirty blocking coefficient is transmitted to an indoor unit or a user terminal, and the dirty blocking coefficient or the average dirty blocking coefficient is displayed on the indoor unit or the user terminal to prompt a user to check the dirty blocking condition of the heat exchanger.

7. The heat exchanger fouling control method according to claim 1, characterized in that: The step of controlling the external fan speed to increase the speed until the external fan speed reaches the maximum speed includes: The external fan windshield is controlled to rise to a preset gear position until the external fan windshield reaches the highest windshield.

8. A heat exchanger fouling control device, characterized in that: include: A first detection module is used to detect the refrigerant pressure value in the outlet pipe of the heat exchanger, and when the refrigerant pressure value is greater than or equal to a first pressure threshold, it is determined that the heat exchanger is dirty and blocked; a second detection module, configured to detect a current exhaust temperature and an air inlet temperature and an air outlet temperature of the heat exchanger, calculate a temperature difference between the air outlet temperature and the air inlet temperature, and calculate a dirty blockage coefficient of the heat exchanger based on the current exhaust temperature and the temperature difference; A first control module is configured to perform frequency reduction control on the compressor and determine whether the dirty and blocking coefficient is greater than or equal to a preset coefficient threshold; a second control module, configured to, when the dirt and blockage coefficient is greater than or equal to the preset coefficient threshold, control the speed of the external fan to increase until the speed of the external fan reaches a maximum speed; The calculation formula of the dirty blocking coefficient is: Ψ=1-(ΔT1 / ΔT)×η η=(Ta / Ti1)×η1×(Td1 / Td)×η2 Among them, Ψ is the dirty blockage coefficient, ΔT1 is the temperature difference, ΔT is the preset standard temperature difference, Td1 is the current exhaust temperature, Td is the preset standard exhaust temperature, Ta is the preset standard outer ring temperature, η1 is the outer ring temperature correction coefficient, η2 is the exhaust temperature correction coefficient, and Ti1 is the air inlet temperature.

9. An air conditioner, characterized in that: The method comprises a computer-readable storage medium storing a computer program and a processor, wherein the outlet pipe of the heat exchanger of the air conditioner is provided with a pressure switch, and the pressure switch is disconnected when it detects that the refrigerant pressure value is greater than the first pressure threshold. When the computer program is read and executed by the processor, the method according to any one of claims 1 to 7 is implemented.

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