A method and system for regulating air conditioning frequency based on connecting pipes

Abstract

An air conditioner frequency regulation method based on a connecting pipe includes the following steps: Step S1: Install pressure sensors at the inlet and outlet of the evaporator, and obtain the first liquid pressure at the evaporator inlet through the pressure sensors; Step S2: Determine whether the first liquid pressure is greater than a pressure threshold. If it is greater than the pressure threshold, obtain the current liquid temperature in the input connecting pipe, and obtain an adjustment coefficient based on the length, diameter, and liquid temperature of the input connecting pipe; Step S3: Adjust the power of the outdoor unit of the air conditioner based on the adjustment coefficient. Adjusting the power of the outdoor unit based on the adjustment coefficient ensures that the power of the outdoor unit remains within a certain operating range, thus maintaining a stable and comfortable indoor temperature. This avoids problems such as decreased cooling effect or increased energy consumption caused by excessively high evaporator pressure, thereby improving the user experience.

Description

Technical Field

[0001] This invention relates to the field of air conditioning control technology, and in particular to an air conditioning frequency control method and system based on connecting pipes. Background Technology

[0002] The air conditioner indoor and outdoor unit connection pipes include an inlet connection pipe and an outlet connection pipe. The outlet connection pipe is responsible for carrying the refrigerant placed in the indoor unit to the outdoor unit to complete the condensation. After condensation, it becomes a high-pressure liquid and re-enters the indoor unit through the inlet connection pipe, forming a circulating refrigeration system.

[0003] Because the installation environment of air conditioning systems affects the length of the connecting pipes between the indoor and outdoor units, the lengths of the pipes may differ. When the air conditioner is running at high power or starting up, a shorter inlet connecting pipe may not provide sufficient space for refrigerant flow and heat dissipation. Simultaneously, a large amount of refrigerant may clog the inlet connecting pipe, hindering the normal flow of refrigerant and ultimately impacting the efficiency and performance of the air conditioning system. Therefore, a method that balances the length of the connecting pipes and the frequency of air conditioning operation is urgently needed. Summary of the Invention

[0004] To address the aforementioned shortcomings, the present invention aims to propose an air conditioner frequency adjustment method and system based on connecting pipes, thereby solving the problem that existing air conditioner outdoor unit power is fixed and cannot self-adjust power based on different connecting pipe lengths.

[0005] To achieve this objective, the present invention adopts the following technical solution: an air conditioning frequency regulation method based on a connecting pipe, comprising the following steps:

[0006] Step S1: Install pressure sensors at the inlet and outlet of the evaporator, and obtain the first liquid pressure at the inlet of the evaporator through the pressure sensors;

[0007] Step S2: Determine whether the first liquid pressure is greater than the pressure threshold. If it is greater than the pressure threshold, obtain the liquid temperature in the current input connecting pipe and obtain the adjustment coefficient based on the length, diameter and liquid temperature of the input connecting pipe.

[0008] Step S3: Adjust the power of the current outdoor unit of the air conditioner based on the adjustment coefficient.

[0009] Preferably, the step S2 in which the adjustment coefficient is obtained based on the length and diameter of the connecting pipe and the liquid temperature is as follows:

[0010] The gas phase coefficient of the current condensate is determined based on the liquid temperature;

[0011] The second liquid pressure at the evaporator outlet is obtained, the pressure difference between the first liquid pressure and the second liquid pressure is obtained, and the current flow rate of the condensate fluid is obtained based on the pressure difference and the gas phase coefficient.

[0012] The first total pressure drop in the pipe is predicted based on the length and diameter of the input connecting pipe and the flow rate of the condensate fluid.

[0013] The adjustment coefficient is the ratio between the standard total pressure drop and the first total pressure drop.

[0014] Preferably, the formula for obtaining the current flow rate of the condensate fluid based on the pressure difference and the gas phase coefficient is as follows:

[0015] ;

[0016] in For pressure difference, , For gas phase coefficient, and These are the densities of the condensate fluid when it vaporizes and when it liquefies, respectively.

[0017] The formula for obtaining the first total pressure drop is as follows:

[0018] ;

[0019] Where f is the pipe friction factor, L is the length of the input connecting pipe, and D is the diameter of the input connecting pipe. Let K be the flow velocity of the condensate fluid, and K be the drag coefficient.

[0020] Preferably, the specific steps of step S3 are as follows:

[0021] The PID controller uses the adjustment coefficient, the length and diameter of the input connecting pipe to obtain the outdoor unit's operating frequency when the condensate flows smoothly into the evaporator, and uses this frequency as the first frequency.

[0022] Obtain the current operating frequency of the outdoor unit as the second frequency, and determine whether the frequency difference between the first frequency and the second frequency is less than the first frequency threshold. If it is less, do not adjust the power of the outdoor unit, and after a preset time, re-execute step S1.

[0023] If the frequency difference is greater than the first frequency threshold and less than the second frequency threshold, then adjust the power of the outdoor unit to the first frequency.

[0024] If the frequency difference is greater than the second frequency threshold, the lowest operating frequency will be used as the power of the outdoor unit. When the first liquid pressure is lower than or equal to the pressure threshold, the power of the outdoor unit will be adjusted to the first frequency.

[0025] Preferably, the formula for obtaining the first frequency is as follows:

[0026] ;

[0027] in , , The gain of the PID controller, For adjustment coefficient, This is the difference between the total pressure drop in the input pipeline and the standard total pressure after the outdoor unit's frequency is adjusted.

[0028] An air conditioning frequency regulation system based on a connecting pipe, characterized in that the air conditioning frequency regulation method based on the connecting pipe includes a pressure sensing module, a data processing module, and an regulation module.

[0029] The pressure sensing module is used to install pressure sensors at the inlet and outlet of the evaporator to obtain the first liquid pressure at the inlet of the evaporator.

[0030] The data processing module is used to determine whether the first liquid pressure is greater than the pressure threshold. If it is greater than the pressure threshold, the liquid temperature in the current input connecting pipe is obtained, and the adjustment coefficient is obtained based on the length, diameter and liquid temperature of the input connecting pipe.

[0031] The adjustment module is used to adjust the power of the current outdoor unit of the air conditioner based on the adjustment coefficient.

[0032] Preferably, the data processing module includes a gas phase coefficient acquisition submodule, a flow rate acquisition submodule, a first total pressure drop acquisition submodule, and an adjustment coefficient acquisition submodule;

[0033] The gas phase coefficient acquisition submodule is used to determine the gas phase coefficient of the current condensate based on the liquid temperature;

[0034] The flow rate acquisition submodule is used to acquire the second liquid pressure at the evaporator outlet, acquire the pressure difference between the first liquid pressure and the second liquid pressure, and acquire the current flow rate of the condensate fluid based on the pressure difference and the gas phase coefficient.

[0035] The first total pressure drop acquisition submodule is used to predict the first total pressure drop in the current pipeline based on the length and diameter of the input connecting pipe and the flow rate of the condensate fluid.

[0036] The adjustment coefficient acquisition submodule is used to use the ratio between the standard total voltage drop and the first total voltage drop as the adjustment coefficient.

[0037] Preferably, the adjustment module includes a frequency acquisition submodule and an adjustment submodule;

[0038] The frequency acquisition submodule is used to obtain the outdoor unit's operating frequency when the condensate flows smoothly into the evaporator from the PID controller, which is based on the adjustment coefficient, the length of the input connecting pipe, and the diameter input value, and uses it as the first frequency.

[0039] The adjustment submodule is used to obtain the current operating frequency of the outdoor unit as the second frequency, and determine whether the frequency difference between the first frequency and the second frequency is less than the first frequency threshold. If it is less, the power of the outdoor unit is not adjusted, and the pressure sensing module is called again after a preset time.

[0040] If the frequency difference is greater than the first frequency threshold and less than the second frequency threshold, then adjust the power of the outdoor unit to the first frequency.

[0041] If the frequency difference is greater than the second frequency threshold, the lowest operating frequency will be used as the power of the outdoor unit. When the first liquid pressure is lower than or equal to the pressure threshold, the power of the outdoor unit will be adjusted to the first frequency.

[0042] One of the above technical solutions has the following advantages or beneficial effects: In this invention, the adjustment coefficient for ensuring the smooth passage of condensate fluid through the evaporator is obtained by inputting the length, diameter, and liquid temperature of the connecting pipe. Then, based on this adjustment coefficient, the power of the outdoor unit is adjusted, ensuring that the outdoor unit's power remains within a certain operating range, thus maintaining a stable and comfortable indoor temperature. This avoids problems such as decreased cooling effect or increased energy consumption due to excessively high evaporator pressure, thereby improving the user experience. Attached Figure Description

[0043] Figure 1 This is a flowchart of one embodiment of the method of the present invention.

[0044] Figure 2 This is a schematic diagram of the structure of one embodiment of the system of the present invention. Detailed Implementation

[0045] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0046] In the description of embodiments of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] like Figures 1-2 As shown, an air conditioner frequency regulation method based on a connecting pipe includes the following steps:

[0049] Step S1: Install pressure sensors at the inlet and outlet of the evaporator, and obtain the first liquid pressure at the inlet of the evaporator through the pressure sensors;

[0050] Step S2: Determine whether the first liquid pressure is greater than the pressure threshold. If it is greater than the pressure threshold, obtain the liquid temperature in the current input connecting pipe and obtain the adjustment coefficient based on the length, diameter and liquid temperature of the input connecting pipe.

[0051] Step S3: Adjust the power of the current outdoor unit of the air conditioner based on the adjustment coefficient.

[0052] In some installation environments, the short length of the inlet connection pipe may not provide enough space for the liquid to flow and dissipate heat. At the same time, a large amount of liquid may clog the inlet connection pipe, affecting the normal flow of refrigerant and ultimately impacting the efficiency and performance of the air conditioning system.

[0053] Therefore, this invention installs pressure sensors at both the inlet and outlet of the evaporator. When the initial pressure at the evaporator inlet exceeds a pressure threshold, it indicates an obstruction to condensate flow. This obstruction is caused by the high temperature of the condensate, resulting in gas-liquid coexistence within the input connecting pipe, thus affecting the overall density of the condensate fluid. This ultimately impacts condensate flow. In this case, it may be necessary to appropriately reduce the power of the outdoor unit to lower the temperature of the condensate entering the input connecting pipe, allowing the condensate fluid to flow smoothly into the evaporator, thereby maintaining the efficiency and performance of the air conditioning system. This invention uses the length and diameter of the input connecting pipe, along with the liquid temperature, to obtain an adjustment coefficient that allows the condensate fluid to pass smoothly through the evaporator. Based on this coefficient, the power of the outdoor unit is adjusted to maintain it within a certain operating range, ensuring a stable and comfortable indoor temperature. This avoids problems such as decreased cooling effect or increased energy consumption due to excessively high evaporator pressure, thereby improving the user experience.

[0054] Preferably, the step S2 in which the adjustment coefficient is obtained based on the length and diameter of the connecting pipe and the liquid temperature is as follows:

[0055] The gas phase coefficient of the current condensate is determined based on the liquid temperature;

[0056] The second liquid pressure at the evaporator outlet is obtained, the pressure difference between the first liquid pressure and the second liquid pressure is obtained, and the current flow rate of the condensate fluid is obtained based on the pressure difference and the gas phase coefficient.

[0057] The first total pressure drop in the pipe is predicted based on the length and diameter of the input connecting pipe and the flow rate of the condensate fluid.

[0058] The adjustment coefficient is the ratio between the standard total pressure drop and the first total pressure drop.

[0059] After passing through the expansion valve of the outdoor unit, the condensed gas becomes a low-temperature, low-pressure liquid. However, due to the high power of the outdoor unit, the liquid pressure and temperature before being processed by the expansion valve are too high. Therefore, not all the condensate becomes liquid after passing through the expansion valve; some gas is still output. Since the output gas is temperature-dependent, the corresponding gas phase coefficient (the ratio of gas to liquid) can be obtained by repeatedly collecting data on the relationship between the liquid temperature and gas volume at the inlet of the input connecting pipe in the laboratory. Because the condensate processing equipment (expansion valve, condenser) is consistent across the same air conditioner model, the relationship between temperature and gas phase coefficient can be determined based on the air conditioner model. Then, the flow velocity of the condensate fluid in the pipe is obtained using variations of Bernoulli's equation and the continuity equation. This eliminates the need for an additional flow velocity sensor, simplifying the air conditioner's control costs.

[0060] After obtaining the condensate flow rate, a pressure drop model is established based on the improved Churchill equation. The first total pressure drop within the pipe is predicted using the length and diameter of the connecting pipe and the condensate flow rate. This first total pressure drop represents the pressure drop at which the condensate can flow smoothly to the evaporator. The standard total pressure drop, which represents the pressure drop at which the condensate can flow smoothly to the evaporator when it is entirely liquid, is calculated. The ratio between these two total pressure drops immediately reveals the required adjustment coefficient. Adjusting the power of the outdoor unit based on this coefficient ensures the condensate flows smoothly into the evaporator, guaranteeing the efficiency and normal operation of the air conditioning system.

[0061] Preferably, the formula for obtaining the current flow rate of the condensate fluid based on the pressure difference and the gas phase coefficient is as follows:

[0062] ;

[0063] in For pressure difference, , For gas phase coefficient, and These are the densities of the condensate fluid when it vaporizes and when it liquefies, respectively.

[0064] The formula for obtaining the first total pressure drop is as follows:

[0065] ;

[0066] Where f is the pipe friction factor, L is the length of the input connecting pipe, and D is the diameter of the input connecting pipe. Let K be the flow velocity of the condensate fluid, and K be the drag coefficient.

[0067] Preferably, the specific steps of step S3 are as follows:

[0068] The PID controller uses the adjustment coefficient, the length and diameter of the input connecting pipe to obtain the outdoor unit's operating frequency when the condensate flows smoothly into the evaporator, and uses this frequency as the first frequency.

[0069] Obtain the current operating frequency of the outdoor unit as the second frequency, and determine whether the frequency difference between the first frequency and the second frequency is less than the first frequency threshold. If it is less, do not adjust the power of the outdoor unit, and after a preset time, re-execute step S1.

[0070] If the frequency difference is greater than the first frequency threshold and less than the second frequency threshold, then adjust the power of the outdoor unit to the first frequency.

[0071] If the frequency difference is greater than the second frequency threshold, the lowest operating frequency will be used as the power of the outdoor unit. When the first liquid pressure is lower than or equal to the pressure threshold, the power of the outdoor unit will be adjusted to the first frequency.

[0072] The first frequency threshold is a dead-zone control feature of this invention, preventing excessive and small-amplitude power adjustments. This avoids frequent adjustments to the outdoor unit's power, which could cause system instability. When the frequency difference is less than the second frequency threshold but greater than the first frequency threshold, the outdoor unit's power is directly adjusted to the first frequency. However, when the frequency difference is greater than the second frequency threshold, it indicates that the difference between the first and second frequencies is too large. Even if the outdoor unit's operating frequency is adjusted to the first frequency, the condensate cannot flow smoothly into the evaporator in a short time, causing continuous system adjustments. Therefore, when the frequency difference is greater than the second frequency threshold, the lowest operating frequency is used as the outdoor unit's power to prevent excessive heating and pressurization of the condenser within a certain time, allowing the first liquid pressure to drop rapidly. When the first liquid pressure is lower than or equal to the pressure threshold, the outdoor unit's power is adjusted back to the first frequency to accelerate the air conditioner's efficiency and ensure it meets the user's cooling needs.

[0073] Preferably, the formula for obtaining the first frequency is as follows:

[0074] ;

[0075] in , , The gain of the PID controller, For adjustment coefficient, This is the difference between the total pressure drop in the input pipeline and the standard total pressure after the outdoor unit's frequency is adjusted.

[0076] An air conditioning frequency regulation system based on a connecting pipe, characterized in that the air conditioning frequency regulation method based on the connecting pipe includes a pressure sensing module, a data processing module, and an regulation module.

[0077] The pressure sensing module is used to install pressure sensors at the inlet and outlet of the evaporator to obtain the first liquid pressure at the inlet of the evaporator.

[0078] The data processing module is used to determine whether the first liquid pressure is greater than the pressure threshold. If it is greater than the pressure threshold, the liquid temperature in the current input connecting pipe is obtained, and the adjustment coefficient is obtained based on the length, diameter and liquid temperature of the input connecting pipe.

[0079] The adjustment module is used to adjust the power of the current outdoor unit of the air conditioner based on the adjustment coefficient.

[0080] Preferably, the data processing module includes a gas phase coefficient acquisition submodule, a flow rate acquisition submodule, a first total pressure drop acquisition submodule, and an adjustment coefficient acquisition submodule;

[0081] The gas phase coefficient acquisition submodule is used to determine the gas phase coefficient of the current condensate based on the liquid temperature;

[0082] The flow rate acquisition submodule is used to acquire the second liquid pressure at the evaporator outlet, acquire the pressure difference between the first liquid pressure and the second liquid pressure, and acquire the current flow rate of the condensate fluid based on the pressure difference and the gas phase coefficient.

[0083] The first total pressure drop acquisition submodule is used to predict the first total pressure drop in the current pipeline based on the length and diameter of the input connecting pipe and the flow rate of the condensate fluid.

[0084] The adjustment coefficient acquisition submodule is used to use the ratio between the standard total voltage drop and the first total voltage drop as the adjustment coefficient.

[0085] Preferably, the adjustment module includes a frequency acquisition submodule and an adjustment submodule;

[0086] The frequency acquisition submodule is used to obtain the outdoor unit's operating frequency when the condensate flows smoothly into the evaporator from the PID controller, which is based on the adjustment coefficient, the length of the input connecting pipe, and the diameter input value, and uses it as the first frequency.

[0087] The adjustment submodule is used to obtain the current operating frequency of the outdoor unit as the second frequency, and determine whether the frequency difference between the first frequency and the second frequency is less than the first frequency threshold. If it is less, the power of the outdoor unit is not adjusted, and the pressure sensing module is called again after a preset time.

[0088] If the frequency difference is greater than the first frequency threshold and less than the second frequency threshold, then adjust the power of the outdoor unit to the first frequency.

[0089] If the frequency difference is greater than the second frequency threshold, the lowest operating frequency will be used as the power of the outdoor unit. When the first liquid pressure is lower than or equal to the pressure threshold, the power of the outdoor unit will be adjusted to the first frequency.

[0090] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0091] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for regulating air conditioning frequency based on connecting pipes, characterized in that, Includes the following steps: Step S1: Install pressure sensors at the inlet and outlet of the evaporator, and obtain the first liquid pressure at the evaporator inlet through the pressure sensors; Step S2: Determine whether the first liquid pressure is greater than the pressure threshold. If it is greater than the pressure threshold, obtain the liquid temperature in the current input connecting pipe and obtain the adjustment coefficient based on the length, diameter and liquid temperature of the input connecting pipe. Step S3: Adjust the power of the outdoor unit of the air conditioner based on the adjustment coefficient; The step S2, which involves obtaining the adjustment coefficient based on the length and diameter of the connecting pipe and the liquid temperature, is as follows: The gas phase coefficient of the current condensate is determined based on the liquid temperature; The second liquid pressure at the evaporator outlet is obtained, the pressure difference between the first liquid pressure and the second liquid pressure is obtained, and the current flow rate of the condensate fluid is obtained based on the pressure difference and the gas phase coefficient. The first total pressure drop in the pipe is predicted based on the length and diameter of the input connecting pipe and the flow rate of the condensate fluid. The adjustment coefficient is the ratio between the standard total pressure drop and the first total pressure drop.

2. The air conditioning frequency regulation method based on a connecting pipe according to claim 1, characterized in that, The formula for obtaining the current flow rate of the condensate fluid based on the pressure difference and the gas phase coefficient is as follows: ； in For pressure difference, , For gas phase coefficient, and These are the densities of the condensate fluid when it vaporizes and when it liquefies, respectively. The formula for obtaining the first total pressure drop is as follows: ； Where f is the pipe friction factor, L is the length of the input connecting pipe, and D is the diameter of the input connecting pipe. Let K be the flow velocity of the condensate fluid, and K be the drag coefficient.

3. The air conditioning frequency regulation method based on a connecting pipe according to claim 1, characterized in that, The specific steps of step S3 are as follows: The PID controller uses the adjustment coefficient, the length and diameter of the input connecting pipe to obtain the outdoor unit's operating frequency when the condensate flows smoothly into the evaporator, and uses this frequency as the first frequency. Obtain the current operating frequency of the outdoor unit as the second frequency, and determine whether the frequency difference between the first frequency and the second frequency is less than the first frequency threshold. If it is less, do not adjust the power of the outdoor unit, and after a preset time, re-execute step S1. If the frequency difference is greater than the first frequency threshold and less than the second frequency threshold, then adjust the power of the outdoor unit to the first frequency. If the frequency difference is greater than the second frequency threshold, the lowest operating frequency will be used as the power of the outdoor unit. When the first liquid pressure is lower than or equal to the pressure threshold, the power of the outdoor unit will be adjusted to the first frequency.

4. The air conditioning frequency regulation method based on a connecting pipe according to claim 3, characterized in that, The formula for obtaining the first frequency is as follows: ； in , , The gain of the PID controller, For adjustment coefficient, This is the difference between the total pressure drop in the input pipeline and the standard total pressure after the outdoor unit's frequency is adjusted.

5. An air conditioning frequency regulation system based on a connecting pipe, characterized in that, The air conditioning frequency regulation method based on the connecting pipe according to any one of claims 1 to 4 includes a pressure sensing module, a data processing module, and an adjustment module; The pressure sensing module is used to install pressure sensors at the inlet and outlet of the evaporator to obtain the first liquid pressure at the inlet of the evaporator. The data processing module is used to determine whether the first liquid pressure is greater than the pressure threshold. If it is greater than the pressure threshold, the liquid temperature in the current input connecting pipe is obtained, and the adjustment coefficient is obtained based on the length, diameter and liquid temperature of the input connecting pipe. The adjustment module is used to adjust the power of the current outdoor unit of the air conditioner based on the adjustment coefficient; The data processing module includes a gas phase coefficient acquisition submodule, a flow rate acquisition submodule, a first total pressure drop acquisition submodule, and an adjustment coefficient acquisition submodule; The gas phase coefficient acquisition submodule is used to determine the gas phase coefficient of the current condensate based on the liquid temperature; The flow rate acquisition submodule is used to acquire the second liquid pressure at the evaporator outlet, acquire the pressure difference between the first liquid pressure and the second liquid pressure, and acquire the current flow rate of the condensate fluid based on the pressure difference and the gas phase coefficient. The first total pressure drop acquisition submodule is used to predict the first total pressure drop in the current pipeline based on the length and diameter of the input connecting pipe and the flow rate of the condensate fluid. The adjustment coefficient acquisition submodule is used to use the ratio between the standard total voltage drop and the first total voltage drop as the adjustment coefficient.

6. The air conditioning frequency regulation system based on a connecting pipe according to claim 5, characterized in that, The adjustment module includes a frequency acquisition submodule and an adjustment submodule; The frequency acquisition submodule is used to obtain the outdoor unit's operating frequency when the condensate flows smoothly into the evaporator from the PID controller, which is based on the adjustment coefficient, the length of the input connecting pipe, and the diameter input value, and uses it as the first frequency. The adjustment submodule is used to obtain the current operating frequency of the outdoor unit as the second frequency, and determine whether the frequency difference between the first frequency and the second frequency is less than the first frequency threshold. If it is less, the power of the outdoor unit is not adjusted, and the pressure sensing module is called again after a preset time. If the frequency difference is greater than the first frequency threshold and less than the second frequency threshold, then adjust the power of the outdoor unit to the first frequency. If the frequency difference is greater than the second frequency threshold, the lowest operating frequency will be used as the power of the outdoor unit. When the first liquid pressure is lower than or equal to the pressure threshold, the power of the outdoor unit will be adjusted to the first frequency.

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