Air conditioner and control method thereof

Abstract

The invention discloses an air conditioner and a control method thereof.The control method comprises the steps that the indoor environment temperature and the outdoor environment temperature are obtained, and the difference between the indoor environment temperature and the outdoor environment temperature is obtained to obtain the current indoor and outdoor environment temperature difference; acquiring an outer fan nominal rotating speed limit range and a pump rotating speed limit range corresponding to the current indoor and outdoor environment temperature difference; acquiring the current rotating speed of the pump; the actual rotating speed upper limit is determined within the nominal rotating speed limiting range of the outer draught fan, and the actual rotating speed upper limit is set as the rotating speed upper limit of the outer draught fan; wherein the closer the current rotating speed is to the pump rotating speed upper limit of the pump rotating speed limit range, the closer the actual rotating speed upper limit is to the nominal rotating speed upper limit of the nominal rotating speed limit range of the outer fan. The invention aims to solve the technical problem of how to prevent refrigerant cutoff at a pump inlet caused by too high rotating speed of an external fan or too low rotating speed of a pump when the indoor and outdoor environment temperature difference is relatively large.

Description

Technical Field

[0001] The invention relates to air conditioning technology, and in particular to an air conditioner and a control method thereof. Background Art

[0002] The energy efficiency requirements of data centers are getting higher and higher. The air conditioning in computer rooms needs to improve the utilization of natural cooling sources. The use of fluorine pump natural cooling function can effectively improve the energy efficiency of the unit.

[0003] Due to the huge advantage of centrifugal pumps in terms of life, existing fluorine pump natural cooling units in computer room air conditioners often use centrifugal pumps as refrigerant transport devices. However, when the refrigerant at the inlet of the centrifugal pump is gasified, it is very easy to cause the failure to form a liquid seal in the centrifugal pump, resulting in the loss of the centrifugal pump head and interruption of flow. When the pump system is running, the change in the speed of the condenser fan can easily cause the refrigerant at the inlet of the centrifugal pump to gasify, causing the system to be interrupted. Summary of the invention

[0004] The present invention aims to solve the technical problem of how to prevent the refrigerant from being cut off at the pump inlet due to the excessive speed of the external fan or the excessive speed of the pump when the temperature difference between indoor and outdoor environments is large.

[0005] To achieve the above object, the present invention provides a control method for an air conditioner, the air conditioner comprising: a condenser for exchanging heat with outdoor air, an evaporator for exchanging heat with indoor air, a pump for driving a refrigerant to circulate between the condenser and the evaporator, and an external fan for driving outdoor air to flow through the condenser;

[0006] The control method comprises:

[0007] Acquire the indoor ambient temperature and the outdoor ambient temperature, and make a difference between the indoor ambient temperature and the outdoor ambient temperature to obtain the current indoor and outdoor ambient temperature difference;

[0008] Obtain the external fan nominal speed limit range and the pump speed limit range corresponding to the current indoor and outdoor ambient temperature difference;

[0009] Get the current speed of the pump;

[0010] Determine an actual speed upper limit within the nominal speed limit range of the external fan, and set the actual speed upper limit as the speed upper limit of the external fan;

[0011] The closer the current speed is to the upper limit of the pump speed in the pump speed limit range, the closer the actual speed upper limit is to the nominal speed upper limit in the external fan nominal speed limit range.

[0012] In an illustrative embodiment, the lower limit of the pump speed in the pump speed limiting range tends to increase as the temperature difference between indoor and outdoor environments increases; and / or

[0013] The lower limit and the upper limit of the nominal speed of the outdoor fan in the nominal speed limit range both tend to decrease with the increase of the temperature difference between the indoor and outdoor environments.

[0014] In an illustrative embodiment, the actual upper speed limit is determined using the following formula:

[0015]

[0016] Among them, Zmax is the actual speed upper limit, fc_min is the nominal speed lower limit, fc_max is the nominal speed upper limit, fp_real is the current speed of the pump, fp_min is the pump speed lower limit, and fp_max is the pump speed upper limit.

[0017] In an illustrative embodiment, it also includes:

[0018] Based on the absolute value of the difference between the indoor ambient temperature and the preset target temperature being less than or equal to the preset temperature tolerance, the speed of the pump is maintained unchanged;

[0019] Based on the difference between the indoor ambient temperature and the preset target temperature being greater than the preset temperature tolerance, the speed of the pump is increased;

[0020] When the difference between the indoor ambient temperature and the preset target temperature is less than the negative value of the preset temperature tolerance, the pump speed is reduced.

[0021] In an exemplary embodiment, the pump speed increase rate and / or speed reduction rate is

[0022]

[0023] In an illustrative embodiment, it also includes:

[0024] Get the current pressure at the outlet of the evaporator, the inlet of the condenser or the outlet of the condenser;

[0025] Based on the fact that the difference between the current pressure and the preset pressure is greater than the preset pressure tolerance, and the difference between the indoor ambient temperature and the preset target temperature is less than or equal to the preset temperature tolerance, the rotation speed of the outdoor fan is increased at a first preset rate.

[0026] In an illustrative embodiment, it also includes:

[0027] Get the current pressure at the outlet of the evaporator, the inlet of the condenser or the outlet of the condenser;

[0028] Based on the fact that the difference between the current pressure and the preset pressure is greater than the preset pressure tolerance and the current rotation speed is equal to the upper limit of the pump rotation speed, the rotation speed of the external fan is increased at a first preset rate.

[0029] In an exemplary embodiment, the first preset rate is negatively correlated with the current indoor and outdoor ambient temperature difference.

[0030] In an illustrative embodiment, it also includes:

[0031] Get the current pressure at the outlet of the evaporator, the inlet of the condenser or the outlet of the condenser;

[0032] When the difference between the current pressure and the preset target pressure is less than the negative value of the preset pressure tolerance, the rotation speed of the external fan is reduced at a second preset speed.

[0033] In an exemplary embodiment, the second preset rate is negatively correlated with the current indoor and outdoor ambient temperature difference.

[0034] In an illustrative embodiment, it also includes:

[0035] Get the current pressure at the outlet of the evaporator, the inlet of the condenser or the outlet of the condenser;

[0036] Based on the absolute value of the difference between the current pressure and the preset target pressure being less than or equal to the preset pressure tolerance, maintaining the speed of the external fan unchanged; and / or

[0037] Based on the fact that the difference between the current pressure and the preset pressure is greater than the preset pressure tolerance, and the difference between the indoor ambient temperature and the preset target temperature is greater than the preset temperature tolerance or the current speed is not equal to the upper limit of the pump speed, the speed of the outdoor fan is maintained unchanged.

[0038] The present application also proposes an air conditioner, which comprises:

[0039] Condenser, used for heat exchange with outdoor air;

[0040] Evaporator, used for exchanging heat with indoor air;

[0041] A pump is used to drive the refrigerant to circulate between the condenser and the evaporator;

[0042] An external fan, used for driving outdoor air to flow through the condenser;

[0043] A detection component, comprising a first temperature sensor for detecting indoor ambient temperature and a second temperature sensor for detecting outdoor ambient temperature;

[0044] a controller, electrically connected to the first temperature sensor, the second temperature sensor, the pump and the external fan;

[0045] Wherein, the controller is configured to execute the control method as described above.

[0046] In the technical solution of the present application, the nominal speed limit range of the outdoor fan and the pump speed limit range are first determined based on the current indoor and outdoor ambient temperature difference. The actual speed upper limit is the upper limit value of the speed of the outdoor fan, and the speed of the outdoor fan is limited to being below the actual speed upper limit. The value range of the actual speed upper limit is the nominal speed limit range of the outdoor fan, and the actual speed upper limit is associated with the current speed of the pump. The greater the current speed of the pump within the pump speed limit range, the greater the value of the actual speed upper limit, and the smaller the current speed of the pump within the pump speed limit range, the smaller the value of the actual speed upper limit, thereby preventing the refrigerant from being interrupted at the pump inlet due to excessive speed of the outdoor fan and / or excessive speed of the pump when the indoor and outdoor ambient temperature difference is large. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0048] Figure 1 This is a structural schematic diagram of an air conditioner in an embodiment of the present application;

[0049] Figure 2 A flow chart of a method for controlling an air conditioner in an embodiment of the present application;

[0050] Figure 3 Schematic diagram of a control flow of an air conditioner in an embodiment of the present application.

[0051] 1. Pump; 2. Throttling element; 3. Evaporator; 4. Condenser; 5. Liquid storage tank; 6. Internal fan; 7. External fan; 8. First pressure sensor; 9. First one-way valve; 10. Second one-way valve; 11. Compressor.

[0052] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0055] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0056] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0058] like Figure 1 As shown, Figure 1 The structure of an air conditioner is shown. The air conditioner can be an inter-row air conditioner or a machine room air conditioner. The air conditioner includes a housing, a pump 1, a throttling element 2, an evaporator 3, a condenser 4, a liquid storage tank 5, an external fan 7 and an internal fan 6. The outlet of the pump 1 is connected to the inlet of the throttling element 2 through a pipeline, the outlet of the throttling element 2 is connected to the inlet of the evaporator 3 through a pipeline, the outlet of the evaporator 3 is connected to the condenser 4 through a pipeline, the condenser 4 is connected to the inlet of the liquid storage tank 5 through a pipeline, and the outlet of the liquid storage tank 5 is connected to the inlet of the pump 1. There is a refrigerant in the pipeline of the refrigeration system, and the refrigerant can be a Freon working medium.

[0059] An inner air duct and an outer air duct are arranged in the housing of the air conditioner. The inlet and outlet of the inner air duct are both connected to the indoor space. The evaporator 3 and the inner fan 6 are both arranged in the inner air duct, and the inner fan 6 can drive the air in the inner air duct to flow from the inlet to the outlet of the inner air duct, so that the indoor air in the indoor space can be sucked in from the inlet of the inner air duct, and after flowing through the evaporator 3, it is output to the indoor space from the outlet of the inner air duct. The indoor air exchanges heat with the evaporator 3 when flowing through the evaporator 3.

[0060] The inlet and outlet of the outer air duct are both connected to the outdoor space. The condenser 4 and the outer fan 7 are both arranged in the outer air duct, and the outer fan 7 can drive the air in the outer air duct to flow from the inlet to the outlet of the outer air duct, so that the outdoor air in the outdoor space can be sucked from the inlet of the outer air duct, and output to the outdoor space from the outlet of the outer air duct after flowing through the condenser 4. The outdoor air exchanges heat with the condenser 4 when flowing through the condenser 4.

[0061] The pump 1 can be an impeller pump 1, such as a centrifugal pump, an axial flow pump or a mixed flow pump. When the pump 1 is in operation, it can suck in liquid refrigerant from the inlet, pressurize it and then output it from the outlet. The refrigerant flows through the throttling element 2, the evaporator 3, the condenser 4 and the liquid storage tank 5 in sequence and then flows back into the pump 1. When the outdoor ambient temperature is low, the air in nature is an abundant natural cold source. The refrigerant absorbs the heat of the air in the indoor environment when passing through the evaporator 3, and releases the heat to the air in the outdoor environment when passing through the condenser 4, thereby achieving refrigeration. Compared with refrigeration using the compressor 11 alone, this refrigeration method has a significant energy-saving effect.

[0062] The air conditioner also includes a detection component and a controller. The detection component includes a first temperature sensor and a second temperature sensor. The first temperature sensor is used to detect the indoor ambient temperature, which can also be referred to as the return air temperature of the evaporator 3. The first temperature sensor is arranged in the inner air duct and upstream of the evaporator 3, and can be arranged at the entrance of the inner air duct. The second temperature sensor is used to detect the outdoor ambient temperature, which can also be referred to as the return air temperature of the condenser 4. The second temperature sensor is arranged in the outer air duct and upstream of the condenser 4, and can be arranged at the entrance of the outer air duct.

[0063] The controller is a logic control unit of the air conditioner, which may be a single chip microcomputer. The controller is electrically connected to the first temperature sensor, the second temperature sensor and the pump 1 .

[0064] like Figure 2 As shown, the present application also proposes a control method for an air conditioner, which is implemented based on the air conditioner as described above. The control method includes the following steps:

[0065] Step S1: The controller obtains the indoor ambient temperature and the outdoor ambient temperature, and subtracts the indoor ambient temperature from the outdoor ambient temperature to obtain the current indoor and outdoor ambient temperature difference;

[0066] The user can send a command to start the pump 1 cooling mode to the air conditioner through a remote control, an intelligent terminal or the control panel of the air conditioner. The command to start the pump 1 cooling mode is used to instruct the pump 1 to operate so that the air conditioner can cool down. After receiving the command to start the pump 1 cooling mode, the controller drives the pump 1, the external fan 7 and the internal fan 6 to operate at their respective initial preset speeds. After the pump 1 is started, the pump 1 sucks the refrigerant from its inlet, and outputs it from its outlet after pressurization, so that the refrigerant circulates between the condenser 4 and the evaporator 3. After the external fan 7 is started, the external fan 7 drives the outdoor air to exchange heat with the refrigerant in the condenser 4 to reduce the temperature of the refrigerant in the condenser 4. After the internal fan 6 is started, the internal fan 6 drives the indoor air to exchange heat with the refrigerant in the evaporator 3 to reduce the temperature of the indoor air.

[0067] When the pump 1 is running, the controller measures the indoor ambient temperature through the first temperature sensor, and measures the outdoor ambient temperature through the second temperature sensor. The controller can obtain the current indoor and outdoor ambient temperature difference by subtracting the indoor ambient temperature from the outdoor ambient temperature.

[0068] Step S2: The controller obtains the external fan nominal speed limit range and the pump speed limit range corresponding to the current indoor and outdoor ambient temperature difference;

[0069] The speed of the pump 1 can determine the flow rate of the refrigerant, which in turn affects the heat exchange efficiency between the condenser 4 and the outdoor air, and the heat exchange efficiency between the evaporator 3 and the indoor air. The higher the speed of the pump 1, the higher the heat exchange efficiency between the condenser 4 and the outdoor air, and the heat exchange efficiency between the evaporator 3 and the indoor air. The heat exchange efficiency between the condenser 4 and the outdoor air, and the heat exchange efficiency between the evaporator 3 and the indoor air will directly affect the cooling capacity of the air conditioner, that is, the higher the speed of the pump 1, the greater the cooling capacity of the air conditioner. The indoor and outdoor ambient temperature difference between the indoor ambient temperature and the outdoor ambient temperature can also affect the cooling capacity of the air conditioner.

[0070] In order to enable the air conditioner to reach a preset cooling capacity under different indoor and outdoor environmental temperature differences, it is necessary to limit the speed of pump 1 under different indoor and outdoor environmental temperature differences. The correspondence between the indoor and outdoor environmental temperature difference and the pump speed limit range when the air conditioner is maintained above the preset cooling capacity can be pre-calibrated. The pump speed limit range is used to limit the size of the speed of pump 1, and the speed of pump 1 can only be limited within the pump speed limit range. The pump speed limit range has a pump speed upper limit and a pump speed lower limit. The pump speed upper limit is the upper limit value of the pump speed limit range, and the pump speed lower limit is the lower limit value of the pump speed limit range. The pump speed lower limit has a tendency to increase with the increase of the indoor and outdoor environmental temperature difference, and the pump speed lower limit can be positively correlated with the indoor and outdoor environmental temperature difference. The pump speed upper limit can be a fixed value, which is determined by the mechanical properties of pump 1 and can be the rated speed of pump 1.

[0071] For example, when the temperature difference between indoor and outdoor environments increases from 0°C to 67°C, the lower limit of the pump speed limit range increases from 45 Hz to 60 Hz, while the upper limit of the pump speed limit range remains unchanged at 60 Hz.

[0072] In this way, the controller of the air conditioner can obtain the pump speed limit range corresponding to the current indoor and outdoor ambient temperature difference according to the current indoor and outdoor ambient temperature difference and the corresponding relationship between the indoor and outdoor ambient temperature difference and the pump speed limit range.

[0073] At the same time, the outdoor fan 7 blows outdoor air toward the condenser 4, and the outdoor air can take away the heat of the refrigerant in the condenser 4. The greater the rotation speed of the outdoor fan 7, the higher the heat exchange efficiency between the outdoor air and the refrigerant.

[0074] In order to maintain the liquid level of the liquid refrigerant in the liquid storage tank 5 above a preset height, it is necessary to limit the rotation speed of the external fan 7 under different indoor and outdoor environmental temperature differences. The correspondence between the indoor and outdoor environmental temperature difference and the external fan nominal speed limit range when the liquid level of the liquid refrigerant in the liquid tank is maintained above a preset height can be pre-calibrated. The external fan nominal speed limit range has a nominal speed lower limit and a nominal speed upper limit, the nominal speed upper limit is the upper limit value of the external fan nominal speed limit range, and the nominal speed lower limit is the lower limit value of the external fan nominal speed limit range. Both the nominal speed lower limit and the nominal speed upper limit have a decreasing trend as the indoor and outdoor environmental temperature difference increases, and the pump speed lower limit may be negatively correlated with the indoor and outdoor environmental temperature difference.

[0075] For example, when the temperature difference between indoor and outdoor environments rises from 0°C to 67°C, the lower limit of the nominal speed limit range of the outdoor fan decreases from 30% of the maximum speed of the outdoor fan to 0, and the upper limit of the nominal speed limit range of the outdoor fan decreases from 70% of the maximum speed of the outdoor fan to 10% of the maximum speed of the outdoor fan.

[0076] In this way, the controller of the air conditioner can obtain the external fan nominal speed limit range corresponding to the current indoor and outdoor ambient temperature difference according to the current indoor and outdoor ambient temperature difference and the corresponding relationship between the indoor and outdoor ambient temperature difference and the external fan nominal speed limit range.

[0077] Step S3: the controller obtains the current speed of the pump 1;

[0078] The speed of the pump 1 is controlled by the controller, and the controller can directly read the current speed information of the pump 1. The air conditioner can also be provided with a speed measuring device electrically connected to the controller, and the current speed of the pump 1 is measured by the speed measuring device. The current speed of the pump 1 is within the pump speed limit range.

[0079] Step S4: the controller determines the actual speed upper limit within the nominal speed limit range of the external fan, and sets the actual speed upper limit as the speed upper limit of the external fan 7;

[0080] The closer the current speed of the pump 1 is to the upper limit of the pump speed in the pump speed limit range, the closer the actual speed upper limit is to the nominal speed upper limit of the external fan nominal speed limit range.

[0081] In the technical solution of this embodiment, the nominal speed limit range of the outdoor fan and the pump speed limit range are first determined based on the current indoor and outdoor ambient temperature difference. The actual speed upper limit is the upper limit value of the speed of the outdoor fan 7, and the speed of the outdoor fan 7 is limited to being only below the actual speed upper limit. The value range of the actual speed upper limit is the nominal speed limit range of the outdoor fan, and the actual speed upper limit is associated with the current speed of the pump 1. The greater the current speed of the pump 1 is within the pump speed limit range, the greater the value of the actual speed upper limit is, and the smaller the current speed of the pump 1 is within the pump speed limit range, the smaller the value of the actual speed upper limit is, thereby preventing the refrigerant from being interrupted at the pump inlet due to the excessive speed of the outdoor fan 7 and / or the low pump speed when the indoor and outdoor ambient temperature difference is large.

[0082] In an illustrative embodiment, in step S4, the actual upper speed limit is calculated using the following formula:

[0083]

[0084] Among them, Zmax is the actual speed upper limit, unit is %; fc_min is the nominal speed lower limit, unit is %; fc_max is the nominal speed upper limit, unit is %; fp_real is the current speed of pump 1, unit is Hz; fp_min is the pump speed lower limit, unit is Hz; fp_max is the pump speed upper limit, unit is Hz.

[0085] Zmax is the actual speed upper limit, fc_min is the nominal speed lower limit, and fc_max is the nominal speed upper limit, all of which are expressed as a percentage of the maximum speed of the external fan.

[0086] In this way, the position of the actual speed upper limit in the nominal speed limit range of the outdoor fan matches the position of the current speed of pump 1 in the pump speed limit range, which can further prevent the refrigerant flow from being interrupted due to excessive speed of the outdoor fan 7 when the temperature difference between indoor and outdoor environments is too large, and the refrigerant flow from being interrupted due to excessive speed of the pump.

[0087] In an illustrative embodiment, step S4 further includes: setting the actual speed lower limit as the speed lower limit of the external fan 7, the actual speed lower limit being equal to the nominal speed lower limit of the nominal speed limit range of the external fan.

[0088] The actual speed lower limit is the lower limit of the speed of the external fan 7, and the speed of the external fan 7 is limited to being above the actual speed lower limit. When the speed of the external fan 7 is equal to the actual speed lower limit, that is, when the speed of the external fan 7 is equal to the nominal speed lower limit, the liquid level of the liquid refrigerant in the liquid storage tank 5 is not lower than the preset height, which can prevent the liquid refrigerant in the liquid storage tank 5 from being too little and causing the refrigerant to be cut off at the pump inlet.

[0089] In an illustrative embodiment, the control method further includes step S5 after step S4;

[0090] Step S5: The controller determines whether the absolute value of the difference between the indoor ambient temperature and the preset target temperature is less than or equal to the preset temperature tolerance, if so, proceeds to step S6, otherwise proceeds to step S7;

[0091] The preset target temperature is the control target value of the indoor environment temperature, which can be set by the user. The preset target temperature range can be 24 to 45°C.

[0092] The preset temperature tolerance is a preset value. The preset temperature tolerance is the allowable deviation between the indoor ambient temperature and the preset target temperature.

[0093] When the preset temperature tolerance is greater than zero, for example, the preset temperature tolerance is 0.5-2°C, if the deviation between the indoor ambient temperature and the preset target temperature is within the preset temperature tolerance, the indoor ambient temperature is not adjusted, so the frequency of adjusting the indoor ambient temperature can be reduced.

[0094] When the preset temperature tolerance is equal to zero, the indoor ambient temperature needs to be adjusted as long as the indoor ambient temperature deviates from the preset target temperature.

[0095] Step S6: The controller maintains the rotation speed of the pump 1 unchanged and enters step S1;

[0096] When the absolute value of the difference between the indoor ambient temperature and the preset target temperature is within the preset temperature tolerance range, the indoor ambient temperature does not need to be adjusted, and the rotation speed of the pump 1 is maintained unchanged.

[0097] Step S7: The controller determines whether the difference between the indoor ambient temperature and the preset target temperature is greater than the preset temperature tolerance, if so, it proceeds to step S8, otherwise it proceeds to step S9;

[0098] Step S8: The controller increases the speed of pump 1 and enters step S1;

[0099] The speed increase rate of pump 1 can be

[0100] When the difference between the indoor ambient temperature and the preset target temperature is greater than the preset temperature tolerance, the indoor ambient temperature is too high and the speed of pump 1 needs to be increased to increase the cooling capacity of the air conditioner, thereby lowering the indoor ambient temperature so that the indoor ambient temperature can be close to the preset target temperature.

[0101] Step S9: The controller reduces the rotation speed of the pump 1 and enters step S1.

[0102] The speed reduction rate of pump 1 can be

[0103] When the difference between the indoor ambient temperature and the preset target temperature is not greater than the preset temperature tolerance and the absolute value of the difference between the indoor ambient temperature and the preset target temperature is not less than or equal to the preset temperature tolerance, that is, when the difference between the indoor ambient temperature and the preset target temperature is less than the negative value of the preset temperature tolerance, at this time, the indoor ambient temperature is too low, and it is necessary to reduce the speed of pump 1 to reduce the cooling capacity of the air conditioner, thereby increasing the indoor ambient temperature so that the indoor ambient temperature can be close to the preset target temperature.

[0104] In this way, the air conditioner can adjust the indoor ambient temperature to the preset target temperature through steps S5 to S9.

[0105] In an illustrative embodiment, the detection assembly further includes a first pressure sensor 8. The first pressure sensor 8 may be disposed at the outlet of the evaporator 3, the inlet of the condenser 4, or the outlet of the condenser 4. The first pressure sensor 8 is used to measure the pressure at the outlet of the evaporator 3, the inlet of the condenser 4, or the outlet of the condenser 4.

[0106] The first pressure sensor 8 is electrically connected to the controller, and the first pressure sensor 8 can send the measurement result to the controller.

[0107] The control method further includes a step S11 after the step S4;

[0108] Step S11: the controller obtains the current pressure of the outlet of the evaporator 3, the inlet of the condenser 4 or the outlet of the condenser 4, and enters step S12;

[0109] The controller measures the current pressure at the outlet of the evaporator 3 , the inlet of the condenser 4 , or the outlet of the condenser 4 via the first pressure sensor 8 .

[0110] Step S12: The controller determines whether the absolute value of the difference between the current pressure and the preset target pressure is less than or equal to the preset pressure tolerance, if so, proceeds to step S13, otherwise proceeds to step S14;

[0111] The preset target pressure is the target value for pressure control at the outlet of the evaporator 3, the inlet of the condenser 4, or the outlet of the condenser 4. In order to maintain stable operation of the air conditioner, the pressure at the outlet of the evaporator 3, the inlet of the condenser 4, or the outlet of the condenser 4 needs to reach the preset target pressure.

[0112] When the first pressure sensor 8 measures the pressure at the outlet of the evaporator 3, the preset target pressure is the pressure control target value at the outlet of the evaporator 3. When the first pressure sensor 8 measures the pressure at the inlet of the condenser 4, the preset target pressure is the pressure control target value at the inlet of the condenser 4. When the first pressure sensor 8 measures the pressure at the outlet of the condenser 4, the preset target pressure is the pressure control target value at the outlet of the condenser 4.

[0113] The preset target pressure is an empirical value and can be calibrated in advance through experiments. The preset target pressure can be in the range of 0.8-1.5Mpa.

[0114] The preset pressure tolerance is a preset value, and is the range by which the pressure at the outlet of the evaporator 3 , the inlet of the condenser 4 , or the outlet of the condenser 4 is allowed to deviate from the preset target pressure.

[0115] When the preset pressure tolerance is greater than zero, for example, the preset pressure tolerance is 0.01-0.06Mpa, if the deviation between the pressure at the outlet of the evaporator 3, the inlet of the condenser 4 or the outlet of the condenser 4 and its preset target pressure is within the preset pressure tolerance, the refrigerant pressure is not adjusted, so the frequency of adjusting the refrigerant pressure can be reduced.

[0116] When the preset pressure tolerance is equal to zero, the refrigerant pressure needs to be adjusted as long as the pressure at the outlet of the evaporator 3, the inlet of the condenser 4 or the outlet of the condenser 4 deviates from its preset target pressure.

[0117] Step S13: The controller maintains the rotation speed of the external fan 7 unchanged and enters step S1;

[0118] The absolute value of the difference between the current pressure and the preset target pressure is less than or equal to the preset pressure tolerance. At this time, there is no need to adjust the refrigerant pressure, and the speed of the external fan 7 is maintained unchanged.

[0119] Step S14: The controller determines whether the difference between the current pressure and the preset pressure is greater than the preset pressure tolerance, if so, it proceeds to step S15, otherwise it proceeds to step S18;

[0120] Step S15: The controller determines whether the difference between the indoor ambient temperature and the preset target temperature is less than or equal to the preset temperature tolerance, if so, it proceeds to step S17, otherwise it proceeds to step S16;

[0121] Step S16: The controller determines whether the current speed of the pump 1 is equal to the upper limit of the pump speed limit range, if so, it goes to step S17, otherwise it goes to step S13;

[0122] Step S17: The controller increases the rotation speed of the external fan 7 at a first preset rate and enters step S1.

[0123] In this way, when the difference between the current pressure and the preset pressure is greater than the preset pressure tolerance, it is necessary to increase the speed of the external fan 7 to make more refrigerant condense into liquid refrigerant, thereby reducing the pressure of the refrigerant in the pipeline. If the difference between the indoor ambient temperature and the preset target temperature is greater than the preset temperature tolerance, the speed of the pump 1 is still increasing to reduce the indoor ambient temperature. At this time, the pressure of the refrigerant is unstable, and the controller does not adjust the speed of the external fan 7. When the difference between the indoor ambient temperature and the preset target temperature is less than or equal to the preset temperature tolerance, the speed of the pump 1 remains unchanged. At this time, the pressure of the refrigerant in the pipeline is reduced by increasing the speed of the external fan 7, which can make the current pressure closer to the preset target pressure, and will not cause the occurrence of the pump inlet refrigerant interruption. If the current speed of the pump 1 is equal to the upper limit of the pump speed within the pump speed limit range, even if the difference between the indoor ambient temperature and the preset target temperature is greater than the preset temperature tolerance, the speed of the pump 1 cannot continue to increase, and can only be maintained at the upper limit of the pump speed. At this time, the speed of the pump 1 is at a relatively large speed, and the pump inlet refrigerant interruption can be avoided when the speed of the external fan 7 is increased.

[0124] Step S18: The controller reduces the rotation speed of the external fan 7 at a second preset rate and enters step S1.

[0125] In this way, when the absolute value of the difference between the current pressure and the preset target pressure is not less than or equal to the preset pressure tolerance, and the difference between the current pressure and the preset pressure is not greater than the preset pressure tolerance, that is, when the difference between the current pressure and the preset target pressure is less than the negative value of the preset pressure tolerance, the rotation speed of the external fan 7 is reduced to allow less refrigerant to condense into liquid refrigerant, thereby increasing the pressure of the refrigerant in the pipeline, and thus making the current pressure closer to the preset target pressure.

[0126] In an exemplary embodiment, in step S17, the first preset rate is negatively correlated with the current indoor and outdoor ambient temperature difference. The first preset rate ranges from increasing the maximum speed of the outdoor fan 7 by 1% every 120 seconds to increasing the maximum speed of the outdoor fan 7 by 1% every 1 second.

[0127] The greater the current temperature difference between the indoor and outdoor environments, the lower the rate of increase of the rotation speed of the outdoor fan 7 , and the smaller the current temperature difference between the indoor and outdoor environments, the higher the rate of increase of the rotation speed of the outdoor fan 7 .

[0128] When the temperature difference between the front room and the outside is large, the risk of refrigerant interruption at the pump inlet is large. At this time, increasing the speed of the external fan 7 at a lower rate can reduce the risk of interruption, making the system run reliably. When the temperature difference between the front room and the outside is small, the risk of interruption is small. At this time, increasing the speed of the external fan 7 at a higher rate can quickly exert the capacity of the air conditioner.

[0129] In an exemplary embodiment, in step S18, the second preset rate is negatively correlated with the current indoor and outdoor ambient temperature difference. The second preset rate ranges from reducing the maximum speed of the outdoor fan 7 by 1% every 120 seconds to reducing the maximum speed of the outdoor fan 7 by 1% every 1 second.

[0130] The greater the current temperature difference between the indoor and outdoor environments, the lower the rate of reduction of the rotation speed of the outdoor fan 7 , and the smaller the current temperature difference between the indoor and outdoor environments, the higher the rate of reduction of the rotation speed of the outdoor fan 7 .

[0131] When the temperature difference between the front room and the outside is large, the risk of flow interruption is large. At this time, reducing the rotation speed of the external fan 7 at a relatively small rate can reduce the risk of flow interruption and make the system run reliably. When the temperature difference between the front room and the outside is small, the risk of flow interruption is small. At this time, reducing the rotation speed of the external fan 7 at a relatively large rate can quickly exert the capacity of the air conditioner.

[0132] In an exemplary embodiment, the air conditioner further comprises a first one-way valve 9, a second one-way valve 10 and a compressor 11. Two ends of the first one-way valve 9 are connected to the outlet of the liquid storage tank 5 and the inlet of the throttling element 2 respectively.

[0133] The first one-way valve 9 can only pass the refrigerant flowing from the liquid storage tank 5 to the throttling element 2. The first one-way valve 9 is connected in parallel with the pump 1.

[0134] The two ends of the second one-way valve 10 are respectively connected to the outlet of the evaporator 3 and the inlet of the condenser 4. The second one-way valve 10 can only pass the refrigerant flowing from the evaporator 3 to the condenser 4. The inlet and outlet of the compressor 11 are respectively connected to the outlet of the evaporator 3 and the inlet of the condenser 4. The compressor 11 is connected in parallel with the second one-way valve 10.

[0135] In this way, when the pump 1 is running and the compressor 11 is not running, the refrigerant circulates in the liquid storage tank 5, the pump 1, the throttling element 2, the evaporator 3, the second one-way valve 10 and the condenser 4; when the compressor 11 is running and the pump 1 is not running, the refrigerant circulates in the liquid storage tank 5, the first one-way valve 9, the throttling element 2, the evaporator 3, the compressor 11 and the condenser 4.

[0136] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for controlling an air conditioner, characterized in that: The air conditioner comprises: a condenser for exchanging heat with outdoor air, an evaporator for exchanging heat with indoor air, a pump for driving the refrigerant to circulate between the condenser and the evaporator, and an external fan for driving outdoor air to flow through the condenser; The control method comprises: Acquire the indoor ambient temperature and the outdoor ambient temperature, and make a difference between the indoor ambient temperature and the outdoor ambient temperature to obtain the current indoor and outdoor ambient temperature difference; Obtain the external fan nominal speed limit range and the pump speed limit range corresponding to the current indoor and outdoor ambient temperature difference; Get the current speed of the pump; Determine an actual speed upper limit within the nominal speed limit range of the external fan, and set the actual speed upper limit as the speed upper limit of the external fan; The closer the current speed is to the upper limit of the pump speed in the pump speed limit range, the closer the actual speed upper limit is to the nominal speed upper limit in the external fan nominal speed limit range.

2. The control method according to claim 1, characterized in that: The lower limit of the pump speed within the pump speed limiting range tends to increase as the temperature difference between indoor and outdoor environments increases; and / or The lower limit and the upper limit of the nominal speed of the outdoor fan in the nominal speed limit range both tend to decrease with the increase of the temperature difference between the indoor and outdoor environments.

3. The control method according to claim 1 or 2, characterized in that: The actual upper speed limit is determined using the following formula: Among them, Zmax is the actual speed upper limit, fc_min is the nominal speed lower limit, fc_max is the nominal speed upper limit, fp_real is the current speed of the pump, fp_min is the pump speed lower limit, and fp_max is the pump speed upper limit.

4. The control method according to claim 1, characterized in that: Also includes: Based on the absolute value of the difference between the indoor ambient temperature and the preset target temperature being less than or equal to the preset temperature tolerance, the speed of the pump is maintained unchanged; Based on the difference between the indoor ambient temperature and the preset target temperature being greater than the preset temperature tolerance, the speed of the pump is increased; When the difference between the indoor ambient temperature and the preset target temperature is less than the negative value of the preset temperature tolerance, the pump speed is reduced.

5. The control method according to claim 4, characterized in that: The pump speed increase rate and / or speed reduction rate is 6. The control method according to claim 4, characterized in that: Also includes: Get the current pressure at the outlet of the evaporator, the inlet of the condenser or the outlet of the condenser; Based on the fact that the difference between the current pressure and the preset pressure is greater than the preset pressure tolerance, and the difference between the indoor ambient temperature and the preset target temperature is less than or equal to the preset temperature tolerance, the rotation speed of the outdoor fan is increased at a first preset rate.

7. The control method according to claim 4, characterized in that: Also includes: Get the current pressure at the outlet of the evaporator, the inlet of the condenser or the outlet of the condenser; Based on the fact that the difference between the current pressure and the preset pressure is greater than the preset pressure tolerance and the current rotation speed is equal to the upper limit of the pump rotation speed, the rotation speed of the external fan is increased at a first preset rate.

8. The control method according to claim 6 or 7, characterized in that: The first preset rate is negatively correlated with the current indoor and outdoor ambient temperature difference.

9. The control method according to claim 4, characterized in that: Also includes: Get the current pressure at the outlet of the evaporator, the inlet of the condenser or the outlet of the condenser; When the difference between the current pressure and the preset target pressure is less than the negative value of the preset pressure tolerance, the rotation speed of the external fan is reduced at a second preset speed.

10. The control method according to claim 9, characterized in that: The second preset rate is negatively correlated with the current indoor and outdoor ambient temperature difference.

11. The control method according to claim 4, characterized in that: Also includes: Get the current pressure at the outlet of the evaporator, the inlet of the condenser or the outlet of the condenser; Based on the absolute value of the difference between the current pressure and the preset target pressure being less than or equal to the preset pressure tolerance, the speed of the external fan is maintained unchanged; and / or Based on the fact that the difference between the current pressure and the preset pressure is greater than the preset pressure tolerance, and the difference between the indoor ambient temperature and the preset target temperature is greater than the preset temperature tolerance or the current speed is not equal to the upper limit of the pump speed, the speed of the outdoor fan is maintained unchanged.

12. An air conditioner, characterized in that: include: Condenser, used for heat exchange with outdoor air; Evaporator, used for exchanging heat with indoor air; A pump is used to drive the refrigerant to circulate between the condenser and the evaporator; An external fan, used for driving outdoor air to flow through the condenser; A detection component, comprising a first temperature sensor for detecting indoor ambient temperature and a second temperature sensor for detecting outdoor ambient temperature; a controller, electrically connected to the first temperature sensor, the second temperature sensor, the pump and the external fan; Wherein, the controller is configured to execute the control method as claimed in any one of claims 1 to 11.

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