Multi-connected heat pump air conditioner and control method

Abstract

The embodiment of the invention provides a multi-connected heat pump air conditioner and a control method, and relates to a cold rain and multi-connected heat pump air conditioner in the air conditioning technology. The indoor evaporator is used for cooling air; the controller is connected with the compressor and the indoor evaporator, and the controller is used for executing first dehumidification operation based on the first evaporation temperature; frosting prediction is conducted on the indoor evaporator, and the defrosting starting moment is determined; at the defrosting starting moment, based on a second evaporation temperature, defrosting operation is executed; the second evaporation temperature is larger than 0 DEG C and smaller than the dew point temperature of the indoor environment; and after defrosting is finished, second dehumidification operation is executed based on the third evaporation temperature till the indoor humidity reaches the target humidity. According to the scheme, non-stop defrosting can be achieved.

Description

TECHNICAL FIELD

[0001] The embodiments of the present application relate to the air conditioning technical field. More particularly, it relates to a multi-connected heat pump air conditioner and a control method. BACKGROUND

[0002] In some scenarios such as lithium battery production, biopharmaceuticals, etc., the air humidity requirement is extremely low. In the above scenarios, multi-connected heat pump air conditioners are often used to dehumidify deeply at a low evaporation temperature. Due to the excessively low evaporation temperature, frost is easily formed on the surface of the cooler, thereby causing humidity fluctuations and even interrupting the dehumidification function.

[0003] Currently, electric heating is mainly used for defrosting during shutdown, and dehumidification cannot be performed during the defrosting period, which easily causes humidity fluctuations and is difficult to meet the user's demand for a continuous and stable low-humidity environment. SUMMARY

[0004] The embodiments of the present application provide a multi-connected heat pump air conditioner and a control method to achieve the effect of defrosting without shutdown.

[0005] In a first aspect, the embodiments of the present application provide a multi-connected heat pump air conditioner, comprising:

[0006] a compressor configured to provide circulating power;

[0007] an indoor evaporator configured to cool air;

[0008] a controller connected to the compressor and the indoor evaporator, the controller being configured to:

[0009] perform a first dehumidification operation based on a first evaporation temperature;

[0010] predict frosting of the indoor evaporator and determine a defrosting start time;

[0011] perform a defrosting operation based on a second evaporation temperature at the defrosting start time; the second evaporation temperature is greater than 0 degrees Celsius and less than the indoor environment dew point temperature;

[0012] after the defrosting ends, perform a second dehumidification operation based on a third evaporation temperature until the indoor humidity reaches a target humidity.

[0013] The above scheme divides the dehumidification into three operation stages, and sets the second evaporation temperature to be greater than 0 degrees Celsius and less than the indoor environment dew point temperature in the second operation stage, so that the dehumidification function is preserved while defrosting, and the defrosting without shutdown is realized.

[0014] In some embodiments, the controller is configured to:

[0015] determine an early defrosting time of the indoor evaporator according to the first evaporation temperature, the indoor humidity, and the supply air volume.

[0016] determining the defrost starting time according to the defrosting time in advance and the preset defrosting time.

[0017] In some embodiments, a frosting rate of the indoor evaporator is determined according to the first evaporating temperature, the indoor humidity and the supply air volume;

[0018] a change relationship of the frost thickness with time is determined based on the frosting rate;

[0019] the defrosting time in advance is determined according to the change relationship of the frost thickness with time.

[0020] In some embodiments, the controller is configured to:

[0021] inputting the first evaporating temperature, the indoor humidity and the supply air volume into a defrosting prediction model to obtain the defrosting time in advance output by the defrosting prediction model.

[0022] In some embodiments, the controller is configured to:

[0023] in the defrosting operation phase, dynamically adjusting the second evaporating temperature according to the indoor humidity so that the indoor humidity is less than a preset humidity.

[0024] In some embodiments, the controller is configured to:

[0025] in the second dehumidifying operation phase, determining a target supply air humidity according to the indoor humidity and the target humidity;

[0026] dynamically adjusting the third evaporating temperature based on the target supply air humidity so that the supply air humidity approaches the target supply air humidity.

[0027] In some embodiments, the controller is configured to:

[0028] determining a response time of the indoor humidity reaching the target humidity based on the indoor environment characteristics, the target humidity and the supply air humidity;

[0029] adjusting a target operation based on the response time so that a time for the indoor humidity to reach the target humidity approaches the response time; the target operation includes at least one of the first dehumidifying operation, the defrosting operation and the second dehumidifying operation.

[0030] In some embodiments, the controller is configured to:

[0031] in the defrosting operation phase, if the indoor humidity exceeds a preset upper limit of humidity, stopping the defrosting operation;

[0032] performing the first dehumidifying operation or the second dehumidifying operation.

[0033] In a second aspect, the embodiments of the present application provide a control method of a multi-connected heat pump air conditioner, comprising:

[0034] a compressor configured to provide circulating power;

[0035] an indoor evaporator configured to cool air;

[0036] The method comprises:

[0037] performing a first dehumidifying operation based on a first evaporation temperature;

[0038] performing frost prediction on the indoor evaporator to determine a defrost starting time;

[0039] performing a defrost operation based on a second evaporation temperature at the defrost starting time; the second evaporation temperature is greater than 0 degrees Celsius and less than an indoor environment dew point temperature;

[0040] performing a second dehumidifying operation based on a third evaporation temperature after the defrost operation until an indoor humidity reaches a target humidity.

[0041] In a third aspect, the embodiments of the present application provide an electrical appliance, comprising: a processor, a transceiver, and a memory; the processor is in communication connection with the transceiver and the memory respectively;

[0042] The memory is configured to store a computer program.

[0043] The transceiver is configured to communicate with an external device.

[0044] The processor is configured to execute the computer program to realize the second aspect and / or various possible implementation manners of the second aspect.

[0045] In a fourth aspect, the embodiments of the present application provide a computer readable storage medium, wherein the computer readable storage medium stores computer execution instructions, and the computer execution instructions are executed by a processor to realize the second aspect and / or various possible implementation manners of the second aspect.

[0046] In a fifth aspect, the embodiments of the present application provide a computer program product, comprising a computer program, and the computer program is executed by a processor to realize the second aspect and / or various possible implementation manners of the second aspect.

[0047] The multi-connected heat pump air conditioner and the control method provided by the embodiment of the application, the multi-connected heat pump air conditioner comprises: a compressor configured to provide circulating power; an indoor evaporator configured to cool air; and a controller connected with the compressor and the indoor evaporator, the controller is configured to: perform a first dehumidification operation based on a first evaporation temperature; perform frost prediction on the indoor evaporator to determine a defrost starting time; perform a defrost operation based on a second evaporation temperature at the defrost starting time; the second evaporation temperature is greater than 0 degrees Celsius and less than an indoor environment dew point temperature; and perform a second dehumidification operation based on a third evaporation temperature after the defrost operation is completed until the indoor humidity reaches a target humidity. The above scheme divides dehumidification into three operation stages, sets the second evaporation temperature to be greater than 0 degrees Celsius and less than the indoor environment dew point temperature in the second operation stage, so that the dehumidification function is maintained while defrosting, the defrosting is realized without stopping, and the humidity fluctuation of the environment is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the application or the implementation manners in the related art, the drawings needed to be used in the embodiment or related art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art according to these drawings.

[0049] Figure 1 A structural schematic diagram of a multi-connected heat pump air conditioner provided by the embodiment of the application;

[0050] Figure 2 A scene schematic diagram of dehumidification provided by the embodiment of the application;

[0051] Figure 3 A schematic diagram of defrosting with stopping provided by the embodiment of the application;

[0052] Figure 4 A humidity change schematic diagram of defrosting with stopping provided by the embodiment of the application;

[0053] Figure 5 A flow schematic diagram of a control method of a multi-connected heat pump air conditioner provided by the embodiment of the application Figure 1 ;

[0054] Figure 6 A frost layer thickness change schematic diagram provided by the embodiment of the application;

[0055] Figure 7 A schematic diagram of zoned operation provided by the embodiment of the application;

[0056] Figure 8 A comparative schematic diagram of defrosting with stopping and defrosting without stopping provided by the embodiment of the application;

[0057] Figure 9 Flowchart of a control method of a multi-connected heat pump air conditioner provided by an embodiment of the present application Figure 2 ;

[0058] Figure 10 Structural diagram of a control device of a multi-connected heat pump air conditioner provided by an embodiment of the present application.

[0059] The specific embodiments of the present application have been shown by the above-described drawings, and will be described in more detail hereinafter. These drawings and the written description are not intended to restrict the scope of the present application by any means, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0060] In order to make the purpose, embodiments and advantages of the present application more clear, the exemplary embodiments of the present application will be described clearly and completely by combining the drawings of the exemplary embodiments of the present application, and obviously, the described exemplary embodiments are only a part of the embodiments of the present application, but not all the embodiments.

[0061] It should be noted that the brief description of the terms in the present application is only for the convenience of understanding the described embodiments, and is not intended to limit the embodiments of the present application. Unless otherwise specified, these terms should be understood according to their ordinary and general meanings.

[0062] In addition, the terms "include" and "have" and any variations thereof are intended to cover but not exclusive inclusion, for example, the product or equipment including a series of components does not have to be limited to the clearly listed components, but can include other components that are not clearly listed or inherent to these products or equipment.

[0063] The terms "first", "second" are only configured for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0064] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0065] Multi-connected heat pump air conditioner is a kind of heat pump air conditioner system which can provide cooling or heating service for multiple rooms simultaneously through connecting multiple indoor units to one outdoor unit by pipelines.

[0066] Figure 1 A structure diagram of a multi-connected heat pump air conditioner provided by the embodiment of the present application is shown in Figure 1 The multi-connected heat pump air conditioner includes one outdoor unit and multiple indoor units. It should be understood that Figure 1 The embodiment of the present application does not limit the number of outdoor units for the structure diagram including three outdoor units.

[0067] The outdoor unit includes a compressor 10, a heat exchanger 20 and a condenser 50, and each indoor unit includes an independent evaporator 30 and a throttling valve 40.

[0068] The outdoor unit and each indoor unit can constitute a cooling or heating cycle. For example, for the indoor unit 1, the unit performs a cooling cycle or a heating cycle through the compressor 10, the heat exchanger 20, the evaporator 30, the throttling valve 40 and the condenser 50. The cooling cycle and the heating cycle include a compression process, a condensation process, an expansion process and an evaporation process, and the temperature adjustment is realized through the heat absorption and heat release processes of the refrigerant.

[0069] The operation process of the unit will be described below taking the cooling cycle as an example.

[0070] The heat exchanger 20 absorbs heat from the air to evaporate the refrigerant into refrigerant gas.

[0071] The compressor 10 compresses the refrigerant gas into a high-temperature and high-pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser 50.

[0072] The condenser 50 is provided with a cooling water inlet and a cooling water outlet which lead into the condenser 50. The cooling water enters the condenser 50 from the cooling water inlet, the condenser 50 condenses the compressed high-temperature and high-pressure gaseous refrigerant into liquid refrigerant, and the heat is released into the cooling water through the condensation process, and the cooling water flows out of the condenser 50 after absorbing heat.

[0073] The liquid refrigerant flowing out of the condenser 50 is subjected to water absorption and drying filtration by a drying filter to absorb the moisture in the refrigerant, so as to ensure the smoothness of the refrigeration pipeline and the normal work of the refrigerant. The dried refrigerant enters the throttling valve 40, which can reduce the pressure of the high-temperature and high-pressure liquid refrigerant, so that the high-temperature and high-pressure liquid refrigerant condensed in the condenser 50 is throttled into low-pressure liquid refrigerant. The low-pressure liquid refrigerant flowing out of the throttling valve 40 enters the evaporator 30.

[0074] The evaporator 30 is provided with a cold water inlet and a cold water outlet, through which cold water enters the evaporator 30. When the liquid refrigerant flows through the evaporator 30, it absorbs heat from the cold water and evaporates into low-temperature and low-pressure refrigerant gas. The temperature of the cold water is lowered and flows out through the cold water outlet. The low-temperature and low-pressure refrigerant gas returns to the heat exchanger 20. The evaporator 30 can transfer heat by using the evaporation heat absorption of the refrigerant to achieve the refrigeration effect.

[0075] When the unit is in heating mode, the flow direction of the refrigerant is switched by the four-way reversing valve, and the whole process is reversed. At this time, the condenser of the outdoor unit becomes an "evaporator", and the evaporator of the indoor unit becomes a "condenser" to release heat to the indoor.

[0076] In some embodiments, the air conditioner further comprises a controller connected with the compressor 10, the evaporator 30, and the throttling valve 40, etc., to control the respective operating parameters during the operation of the air conditioner.

[0077] Figure 2 A scene diagram for dehumidification using a multi-connected heat pump air conditioner is provided for the embodiments of the present application, as shown in Figure 2

[0078] The return air from the factory or outdoor fresh air first passes through the "front surface cooling" for pre-cooling and preliminary dehumidification.

[0079] The cooled and saturated air enters the dehumidification area of the wheel. The wheel is filled with moisture-absorbing materials (such as silica gel and molecular sieve), which can deeply absorb the moisture in the air, making the air very dry.

[0080] The dry and high-temperature air is cooled to an appropriate temperature by "back surface cooling" and is sent into the factory for dehumidification.

[0081] The exhaust air (return air) from the factory is sent to the regeneration area of the wheel after being heated by the regenerative heater. The heat of the exhaust air evaporates the moisture contained in the moisture-absorbing materials of the wheel, which is carried away, thereby restoring the dry state of the wheel and enabling continuous dehumidification.

[0082] The moist and hot air that has absorbed moisture is discharged to the outdoor by the regenerative fan or enters the next dehumidification cycle.

[0083] In the system shown in Figure 2 The "front surface cooling" and "back surface cooling" are evaporators of different indoor units in the multi-connected heat pump air conditioner, and the regenerative heating can be a condenser in the multi-connected heat pump air conditioner.

[0084] ​As described above, when the pre-cooling and preliminary dehumidification of the return air from the factory building or outdoor fresh air is performed, the evaporating temperature of the pre-cooling is too low, which easily causes the temperature of the pre-cooling coil to be lower than 0℃, so that the pre-cooling coil is frosted and cannot normally dehumidify.

[0085] To solve the problem of frosting on the evaporator surface, the conventional method is to stop the multi-connected heat pump air conditioner when the frost thickness reaches a certain thickness, and to defrost by electric heating. Figure 3 and Figure 4 As shown in the above two figures, the multi-connected heat pump air conditioner cannot dehumidify during the stoppage defrosting, and the environmental humidity fluctuates by 40% during the stoppage defrosting, which easily causes loss to the user.

[0086] To solve the above problems, the embodiment of the present application provides a multi-connected heat pump air conditioner and a control method, which divides the dehumidification process into multiple stages, in the first stage, the evaporating temperature is lowered to increase the dehumidification capacity of the unit, in the second stage, the evaporating temperature is raised to be higher than 0℃, so that the unit can defrost while maintaining a certain dehumidification capacity, and the defrosting is realized without stopping.

[0087] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described in some embodiments.

[0088] Figure 5 The flowchart of the control method of the multi-connected heat pump air conditioner provided by the present application is shown in the figure, and the execution subject of the embodiment of the present application can be the controller or control module of the multi-connected heat pump air conditioner (hereinafter referred to as air conditioner). Figure 5 As shown in the figure, the method comprises the following steps.

[0089] S501, based on the first evaporating temperature, a first dehumidification operation is performed.

[0090] In some embodiments, the evaporating temperature refers to the temperature of the refrigerant when it changes from liquid state to gaseous state in the evaporator. The evaporating temperature corresponds to the evaporating pressure inside the evaporator. The higher the evaporating pressure, the higher the evaporating temperature, and the lower the evaporating pressure, the lower the evaporating temperature.

[0091] In some embodiments, the first evaporating temperature (Te1) is lower than the evaporating temperature (Te0) when the conventional air conditioner is running.

[0092] In some embodiments, the first evaporating temperature can be a value preset according to the physical characteristics and dehumidification efficiency of the unit. For example, the first evaporating temperature is set to -10℃.

[0093] In some embodiments, the opening degree of the corresponding expansion valve of the evaporator can be adjusted to adjust the evaporation pressure of the evaporator, so as to adjust the normal evaporation temperature to the first evaporation temperature.

[0094] In some embodiments, the suction volume or rotating speed of the compressor can also be adjusted to adjust the evaporation pressure of the evaporator, so as to adjust the normal evaporation temperature to the first evaporation temperature.

[0095] S502, frost prediction is performed on the indoor evaporator to determine a defrost starting time.

[0096] In some embodiments, the defrost starting time can refer to the time when the air conditioner starts to perform the defrost operation.

[0097] For example, when the air conditioner runs at the normal evaporation temperature for dehumidification, the defrost needs to be performed after 60 minutes of running, and this time is referred to as the defrost starting time.

[0098] In some embodiments, the lower the evaporation temperature, the lower the temperature of the evaporator surface, and the stronger the ability of the evaporator to capture moisture (condensed into frost) from the air, and thus the faster the frost formation rate of the evaporator.

[0099] In some embodiments, the frost formation on the evaporator surface is related to the evaporation temperature, the air supply volume of the air conditioner, and the moisture content of the air. The defrost starting time can be determined based on the evaporation temperature, the air supply volume of the air conditioner, and the moisture content of the air.

[0100] For example, the advance defrost time of the indoor evaporator is determined according to the first evaporation temperature, the indoor humidity, and the air supply volume; and the defrost starting time is determined according to the advance defrost time and a preset defrost time.

[0101] For example, the normal defrost time is 60 minutes, and the defrost needs to be performed 25 minutes in advance (i.e., the defrost starts at 35 minutes) at the first evaporation temperature, and the 25 minutes is the advance defrost time.

[0102] In a possible implementation, the frost formation rate of the indoor evaporator can be determined according to the first evaporation temperature, the indoor humidity, and the air supply volume; the change relationship of the frost layer thickness with time is determined based on the frost formation rate; and the advance defrost time is determined according to the change relationship of the frost layer thickness with time.

[0103] For example, the frost amount is related to the moisture content of the air (the higher the moisture content, the more the frost amount), the air supply volume of the air conditioner (the larger the air supply volume, the more the frost amount), and the evaporation temperature (the lower the evaporation temperature, the more the frost amount). ), the air supply volume (F), and the difference between the saturation humidity content corresponding to the evaporator surface temperature and the air dew point temperature is proportional. Therefore, a physical equation corresponding to the frosting rate can be established based on the heat and mass exchange principle. For example, the frosting rate = .

[0104] After establishing the physical equation corresponding to the frosting rate, the physical equation corresponding to the frosting rate can obtain the relationship between the evaporator surface frost layer thickness and time as shown in Figure 6 After determining the relationship between the frost layer thickness and time, the frost layer thickness on the evaporator surface at the current time can be determined based on the running time of the air conditioner, and the defrosting time in advance can be determined based on the frost layer thickness.

[0105] For example, according to the relationship between the frost layer thickness and time, it is determined that the frost layer thickness increases from 0 to the threshold value that needs to be defrosted for 25 minutes, which is the determined defrosting time in advance.

[0106] If the conventional defrosting is at t1=60 minutes, but in the current low Te1 mode, the frosting reaches the threshold value only T1=25 minutes, then the air conditioner will defrost in advance at t0=60-25=35 minutes (i.e. the 35th minute), that is, the defrosting start time is the 35th minute.

[0107] In one possible implementation, the first evaporating temperature, the indoor humidity, and the air supply volume can be input into the defrosting prediction model to obtain the defrosting time in advance output by the defrosting prediction model.

[0108] The defrosting prediction model can be a mapping relationship of the defrosting time in advance learned and established based on historical operation data.

[0109] For example, the evaporating temperature Te1=-10°C, the air supply humidity H1=8g / kg, and the air volume F=5000m³ / h are input into the defrosting prediction model, and the defrosting prediction model can output T1=25 minutes based on the mapping relationship.

[0110] In one possible implementation, the frost layer thickness satisfies the formula as shown below:

[0111]

[0112] wherein, is the frost layer thickness, is the dew point temperature, is the saturation evaporation temperature, is the running time, and β and K are constants.

[0113] The above formula can be iteratively solved to determine the frost layer thickness on the evaporator surface at the current time, and the defrosting time in advance can be determined based on the frost layer thickness.

[0114] S503, at the defrost starting moment, performing a defrost operation based on the second evaporation temperature.

[0115] In some embodiments, the second evaporation temperature is greater than 0 degrees Celsius and less than the indoor environment dew point temperature.

[0116] The dew point temperature refers to the temperature at which the air cools to a saturated state (relative humidity reaches 100%) without changing the humidity content. That is, the temperature at which the water vapor in the air begins to condense into dew.

[0117] When the second evaporation temperature is greater than 0 degrees Celsius, the temperature conducted to the surface of the evaporator is also higher than 0 degrees Celsius, thereby melting the frost layer on the surface of the evaporator. When the second evaporation temperature is less than the indoor environment dew point temperature, the evaporator can maintain a certain dehumidification capacity, thereby reducing the indoor humidity fluctuation during defrosting.

[0118] In some embodiments, the second evaporation temperature can be a preset value based on the characteristics of the air conditioner and prior knowledge.

[0119] In some embodiments, during the defrosting, although the air conditioner has a certain dehumidification capacity, the defrosting operation still causes the indoor humidity to rise. To avoid excessive indoor humidity fluctuation, the second evaporation temperature can be dynamically adjusted based on the indoor humidity, so that the indoor humidity is less than the preset humidity.

[0120] For example, during defrosting, if the indoor humidity rises too quickly and approaches the preset humidity, the initial second evaporation temperature can be lowered to enhance the dehumidification capacity of the air conditioner. If the indoor humidity is relatively stable and much less than the preset humidity, the initial second evaporation temperature can be increased to speed up the defrosting and reduce the defrosting duration.

[0121] In some embodiments, a fuzzy-PID control strategy can be used to dynamically adjust the second evaporation temperature during defrosting to find a balance point between the indoor humidity not exceeding the standard and the defrosting time being short. The input of the fuzzy-PID is the difference between the current indoor humidity and the preset humidity, the output is the second evaporation temperature, and the constraint is that the second evaporation temperature is greater than 0 degrees Celsius and less than the indoor environment dew point temperature.

[0122] In some embodiments, if during the dynamic adjustment of the second evaporation temperature during defrosting, the indoor humidity exceeds the preset upper limit of the humidity, it indicates that the defrosting operation causes a large fluctuation in the indoor humidity. To reduce the impact of excessive indoor humidity on the user, the defrosting operation can be stopped, and the first dehumidification operation or the second dehumidification operation can be performed to reduce the indoor humidity.

[0123] In some embodiments, after the humidity in the room drops to less than the preset humidity after performing the first dehumidifying operation or the second dehumidifying operation, the air conditioner can re-perform the defrosting operation,

[0124] S504, after the defrosting ends, performing a second dehumidifying operation based on a third evaporating temperature until the humidity in the room reaches a target humidity.

[0125] In some embodiments, whether the defrosting ends can be determined based on the evaporator surface temperature. For example, when the evaporator surface temperature continuously exceeds the freezing point for a preset time length, it indicates that the defrosting is basically completed.

[0126] In some embodiments, the defrosting can also be determined to end when the defrosting time length is greater than a preset defrosting time length threshold. The defrosting time length threshold can be set to a time length based on historical data and the current frost thickness.

[0127] In some embodiments, the second dehumidifying operation can belong to a regular dehumidifying operation.

[0128] In some embodiments, the third evaporating temperature can be the same as the regular evaporating temperature, or can be different from the regular evaporating temperature. The embodiments of the present application do not limit this.

[0129] In some embodiments, since the second dehumidifying operation belongs to a regular dehumidifying operation, the corresponding third evaporating temperature can be determined based on the target supply air humidity.

[0130] The target supply air humidity can be determined based on the target humidity to be reached in the room and the current humidity in the room. For example, when the difference between the target humidity and the current humidity in the room is large, the target supply air humidity can be set to be lower. When the difference between the target humidity and the current humidity in the room is small, the target supply air humidity can be set to be higher.

[0131] After determining the target supply air humidity, the third evaporating temperature can be determined based on a preset mapping relationship between the supply air humidity and the evaporating temperature.

[0132] In some embodiments, during the execution of the second dehumidifying operation, the target supply air humidity can be dynamically adjusted based on the actual supply air humidity to adjust the third evaporating temperature, so that the supply air humidity approaches the target supply air humidity.

[0133] For example, during the execution of the second dehumidifying operation, the core target of the air conditioner has changed from “fast dehumidifying” to “precise humidity control”, at this time, the third evaporating temperature can be dynamically adjusted in a PID control manner, so that the humidity in the room smoothly transitions to the target humidity, avoiding large fluctuations in humidity. The input of the PID can be the difference between the actual supply air humidity and the target supply air humidity, and the output can be the third evaporating temperature.

[0134] In summary, as shown in Figure 7 The control method of the multi-connected heat pump air conditioner provided by the embodiments of the present application divides the evaporation temperature into three regions, i.e., a low evaporation temperature region H4-H5 (evaporation temperature Te1), a high evaporation temperature region H5-H6 (evaporation temperature Te2), and a normal control region H6-H7-H8 (evaporation temperature Te3). In the low evaporation temperature region H4-H5, the evaporation temperature is lowered to Te1, the dehumidification capacity of the air handling unit is increased, and the defrosting time is advanced from t1 to t0 (T1=t1-t0). In the high evaporation temperature region H5-H6, the evaporation temperature is raised to Te2 (Te2>0℃ and Te2<the room dew point temperature), and the dehumidification function is maintained during defrosting. In the normal control region H6-H7-H8, the target humidity of the air outlet is controlled to dynamically adjust Te3, and after a period of time, the humidity content tends to balance to the target value. The above scheme can realize on-line defrosting, reduce the humidity fluctuation in the room during defrosting, and thus meet the user's demand for continuous and stable low-humidity environment.

[0135] As shown in Figure 8 Compared with the electric heating off-line defrosting, the on-line defrosting provided by the embodiments of the present application can significantly improve the dehumidification capacity. When the electric heating defrosting is performed, the peak value of the indoor humidity content increases to 8.1 g / kg 干空气 , while the peak value of the indoor humidity content during the defrosting is only 5.7 g / kg 干空气 .

[0136] Figure 9 The flowchart of the control method of the multi-connected heat pump air conditioner provided by the embodiments of the present application is shown in Figure 2 As shown in Figure 9 , the method comprises the following steps.

[0137] S901, determining the response time of the indoor humidity to reach the target humidity based on the indoor environmental characteristics, the target humidity, and the supply air humidity.

[0138] In some embodiments, the indoor environmental characteristics can include the room volume, the room humidity, the humidity source term, etc. The humidity source term can refer to all sources of releasing water vapor (i.e., increasing the air humidity content) into the room air.

[0139] When the air conditioner is used to dehumidify the room, without considering the frosting, the indoor humidity can satisfy the following differential equation according to the law of conservation of mass:

[0140]

[0141] wherein the room volume is V0, the current room humidity is H(t), the supply air humidity is H1, and the humidity source term is H sThe air supply volume of the air conditioner is F1, and the return air volume of the room is F2 (usually, F1=F2).

[0142] Solving the above differential equation, the expression of the humidity change over time is as follows:

[0143]

[0144] Where H0 is the initial humidity.

[0145] The response time t to reach the target humidity H is as follows:

[0146]

[0147] S902, adjust the target operation based on the response time, so that the time for the indoor humidity to reach the target humidity tends to the response time; the target operation includes at least one of the first dehumidification operation, the defrosting operation, and the second dehumidification operation.

[0148] In some embodiments, when dehumidifying, the user usually wants to reach the target humidity in the shortest time. After determining the response time of the indoor humidity reaching the target humidity, the process of three-zone evaporation temperature dehumidification and defrosting can be adjusted based on the response time to complete the dehumidification task as much as possible within the response time.

[0149] For example, when performing the first dehumidification task, it is determined based on the defrosting prediction model that the defrosting operation needs to be performed after 30 minutes, but based on the response time determination, the first dehumidification operation needs to be performed for 40 minutes to complete the dehumidification task within the response time.

[0150] At this time, the air conditioner will face the following two options:

[0151] Option A: Perform the first dehumidification operation for 40 minutes or close to 40 minutes, but the frost will exceed the safety threshold, increasing the risk to the air conditioner.

[0152] Option B: Perform the first dehumidification operation for 30 minutes, then perform the defrosting operation, but the dehumidification task cannot be completed within the response time.

[0153] In this case, the air conditioner can select the operation to be performed based on a predefined priority.

[0154] For example, the priority can be as follows:

[0155] 1. First priority: equipment safety

[0156] Ensure that core components such as compressors and fans are not damaged due to excessive frost or liquid impact.

[0157] 2. Second priority: Process security

[0158] Ensure that the room humidity does not exceed the absolute upper limit of the process requirement (i.e., cannot "exceed the standard").

[0159] 3. Third priority: Energy efficiency and operation economy

[0160] Under the premise of meeting the above two conditions, try to save energy, reduce defrosting frequency, and shorten defrosting time.

[0161] Under the above priority, the air conditioner will determine whether delaying defrosting for 10 minutes will cause the frost layer to be too thick, causing problems such as fan overload, permanent damage to the heat exchanger, or compressor liquid knock. If the risk assessment considers that delaying defrosting for 10 minutes is extremely risky, option B will be executed.

[0162] If the device safety risk is controllable, the air conditioner will further assess whether the humidity will exceed the standard after 30 minutes of defrosting. If the risk assessment considers that the risk of humidity exceeding the standard is extremely high, it will choose to delay defrosting and prioritize core process security. For example, defrosting is performed after 35 minutes of operation.

[0163] In the case where the device safety risk is controllable and the humidity does not exceed the standard, the air conditioner can choose the path with lower total cost based on the cost of performing dehumidification and defrosting operations.

[0164] For example, the cost of performing dehumidification and defrosting operations can be determined based on a pre-set cost function.

[0165] For example, the cost function may include:

[0166] Cost of option A (defrosting in advance):

[0167] Cost_humidity = k1 * (predicted humidity deviation)

[0168] Cost_time = k2 * (predicted progress delay time)

[0169] Cost of option B (delaying defrosting):

[0170] Cost_energy = k3 * (additional energy consumption due to COP drop caused by frost)

[0171] Cost_risk = k4 * (potential device life loss due to increased frost)

[0172] Cost_defrost_time = k5 * (longer defrosting time required due to thicker frost layer)

[0173] The air conditioner will calculate total cost_A = Cost_humidity + Cost_time and total cost_B = Cost_energy + Cost_risk + Cost_defrost_time, and then execute the solution with lower total cost.

[0174] It should be understood that the adjustment mode of the defrosting operation and the second dehumidifying operation based on the response time is similar, and details are not repeated here.

[0175] In summary, the control method of the multi-connected heat pump air conditioner provided by the embodiments of the present application can dynamically regulate and control the three-stage operation of the dehumidifying process through the response time, so as to ensure "non-stop defrosting" and ultimately achieve the core purpose of "quickly and stably reaching the target humidity".

[0176] On the basis of the above-mentioned embodiments, the embodiments of the present application further provide a control device of a multi-connected heat pump air conditioner.

[0177] Figure 10 A structural schematic diagram of a control device 100 of a multi-connected heat pump air conditioner provided by the embodiments of the present application is shown in FIG. 1, which includes: Figure 10

[0178] A first dehumidifying module 1001 is configured to perform a first dehumidifying operation based on a first evaporation temperature.

[0179] A determination module 1002 is configured to predict frosting of an indoor evaporator and determine a defrosting start time.

[0180] A defrosting module 1003 is configured to perform a defrosting operation based on a second evaporation temperature at the defrosting start time. The second evaporation temperature is greater than 0 degrees Celsius and less than the indoor environment dew point temperature.

[0181] A second dehumidifying module 1004 is configured to perform a second dehumidifying operation based on a third evaporation temperature after the defrosting ends until the indoor humidity reaches a target humidity.

[0182] In some embodiments, the determination module 1002 is configured to determine an early defrosting time of the indoor evaporator according to the first evaporation temperature, the indoor humidity, and a supply air volume, and determine the defrosting start time according to the early defrosting time and a preset defrosting time.

[0183] In some embodiments, the determination module 1002 is configured to determine a frosting rate of the indoor evaporator according to the first evaporation temperature, the indoor humidity, and the supply air volume, determine a change relationship of a frost layer thickness with time based on the frosting rate, and determine the early defrosting time according to the change relationship of the frost layer thickness with time.

[0184] In some embodiments, the determination module 1002 is configured to input the first evaporation temperature, the indoor humidity, and the supply air volume into a defrosting prediction model to obtain the early defrosting time output by the defrosting prediction model.

[0185] ​In some embodiments, the defrosting module 1003 is configured to dynamically adjust the second evaporation temperature according to the indoor humidity so as to make the indoor humidity less than the preset humidity during the defrosting operation phase.

[0186] In some embodiments, the second dehumidifying module 1004 is configured to determine a target supply air humidity according to the indoor humidity and the target humidity during the second dehumidifying operation phase; and dynamically adjust the third evaporation temperature based on the target supply air humidity so as to make the supply air humidity approach the target supply air humidity.

[0187] In some embodiments, the determining module 1002 is configured to determine a response time for the indoor humidity to reach the target humidity based on the indoor environment characteristics, the target humidity and the supply air humidity; and adjust the target operation based on the response time so as to make the time for the indoor humidity to reach the target humidity approach the response time; the target operation includes at least one of the first dehumidifying operation, the defrosting operation and the second dehumidifying operation.

[0188] In some embodiments, the defrosting module 1003 is configured to stop the defrosting operation if the indoor humidity exceeds a preset upper limit of the humidity during the defrosting operation phase; and perform the first dehumidifying operation or the second dehumidifying operation.

[0189] The control device of the multi-connected heat pump air conditioner provided by the embodiments of the present application can perform the control method of the air conditioner shown in any of the above embodiments, and has similar principles and technical effects, which will not be described herein again.

[0190] The present application further provides an electronic device, which can include a transceiver, a processor and a memory. The electronic device can be the controller in any of the above embodiments.

[0191] The processor executes computer execution instructions stored in the memory, so that the processor performs the scheme in the above embodiments. The processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP) and the like; and can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0192] The memory is connected with the processor through a system bus and completes mutual communication. The memory is used for storing computer program instructions.

[0193] The transceiver can perform receiving and sending data and instructions.

[0194] Optionally, the electronic device can further include a communication interface, through which the electronic device can communicate with external or internal devices, for example, a client (e.g., a mobile phone, a tablet). In a specific implementation, if the communication interface, the memory, and the processor are implemented independently, the communication interface, the memory, and the processor can be connected to each other through a bus and complete communication with each other.

[0195] The system bus can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The system bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or only one type of bus. The transceiver is used to realize communication between the database access device and other computers (e.g., a client, a read-write library, and a read-only library). The memory can include a random access memory (RAM) and can also include a non-volatile memory.

[0196] Optionally, in a specific implementation, if the communication interface, the memory, and the processor are integrated on a chip, the communication interface, the memory, and the processor can complete communication through an internal interface.

[0197] The present application also provides a computer program product, including a computer program, which is executed by a processor to implement the above method.

[0198] The present application also provides a computer readable storage medium, which stores computer execution instructions, and when a processor executes the computer execution instructions, the above method is implemented.

[0199] The above readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as a static random access memory (SRAM), an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a programmable read-only memory (PROM), a read-only memory (ROM), a magnetic storage, a flash memory, a magnetic disk, or an optical disk. The readable storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0200] An example readable storage medium is coupled to the processor such that the processor can read information from the readable storage medium and can write information to the readable storage medium. Of course, the readable storage medium can also be a part of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in the device.

[0201] The division of units is only a logical functional division, and in actual implementation, there can be another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0202] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0203] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit.

[0204] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the part of the present application that essentially contributes to the prior art or the part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method of each embodiment of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0205] Those skilled in the art can understand that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware. The foregoing program can be stored in a computer readable storage medium. The program executes to perform the steps of the above-mentioned method embodiments; and the foregoing storage medium includes various media capable of storing program codes, such as ROM, RAM, magnetic disk, or optical disk.

[0206] Finally, it should be noted that other embodiments of the present application will readily occur to those skilled in the art upon consideration of the specification and practice of the present application disclosed herein. The present application is intended to include all such variations as fall within the general scope of the application, and includes the generic principles disclosed and the best mode known to the inventors to be currently practiced as well as variations thereof, without departing from the scope of the present application as defined by the claims. The specification and examples give the best application of the present application as known to at least one of the inventors at the time of the filing of this application. It is to be understood that since numerous modifications and changes will readily occur to those skilled in the art, the application is not to be limited to the exact construction and operation as illustrated and described. Accordingly, all such variations are intended to be included within the scope of the present application as defined in the claims. The application is to be limited only by the claims.

Claims

1. A multi-connected heat pump air conditioner, characterized by, The method comprises: a compressor for providing circulating power; an indoor evaporator for cooling air; a controller connected with the compressor and the indoor evaporator, the controller being configured to: perform a first dehumidification operation based on a first evaporation temperature; perform frost prediction on the indoor evaporator to determine a defrost starting time; perform a defrost operation based on a second evaporation temperature at the defrost starting time, the second evaporation temperature being greater than 0 degree Celsius and less than a dew point temperature of an indoor environment; perform a second dehumidification operation based on a third evaporation temperature after the defrost operation is completed until an indoor humidity reaches a target humidity.

2. The air conditioner according to claim 1, wherein The controller is configured to: determine an early defrost time of the indoor evaporator according to the first evaporation temperature, the indoor humidity, and a supply air volume; determine the defrost starting time according to the early defrost time and a preset defrost time.

3. The air conditioner according to claim 2, wherein The controller is configured to: determine a frost formation rate of the indoor evaporator according to the first evaporation temperature, the indoor humidity, and the supply air volume; determine a relationship between a frost thickness and time based on the frost formation rate; determine the early defrost time according to the relationship between the frost thickness and time.

4. The air conditioner according to claim 2, wherein The controller is configured to: input the first evaporation temperature, the indoor humidity, and the supply air volume into a defrost prediction model to obtain the early defrost time output by the defrost prediction model.

5. The air conditioner according to any one of claims 1 to 4, characterized by The controller is configured to: dynamically adjust the second evaporation temperature according to the indoor humidity during the defrost operation to make the indoor humidity less than a preset humidity.

6. The air conditioner according to any one of claims 1 to 4, characterized by The controller is configured to: determine a target supply air humidity according to the indoor humidity and the target humidity during the second dehumidification operation; dynamically adjust the third evaporation temperature based on the target supply air humidity to make the supply air humidity approach the target supply air humidity.

7. The air conditioner according to any one of claims 1 to 4, characterized by The controller is configured to: determine a response time for the indoor humidity to reach the target humidity based on characteristics of the indoor environment, the target humidity, and a supply air humidity; adjust a target operation based on the response time to make a time for the indoor humidity to reach the target humidity approach the response time, the target operation including at least one of the first dehumidification operation, the defrost operation, and the second dehumidification operation.

8. The air conditioner according to claim 5, wherein The controller is configured to: stop performing the defrost operation if the indoor humidity exceeds a preset upper limit of humidity during the defrost operation; perform the first dehumidification operation or the second dehumidification operation.

9. A control method of a multi-connected heat pump air conditioner, characterized by, The method comprises: a compressor for providing circulating power; an indoor evaporator for cooling air; The method comprises: performing a first dehumidification operation based on a first evaporation temperature; performing frost prediction on the indoor evaporator to determine a defrost starting time; performing a defrost operation based on a second evaporation temperature at the defrost starting time, the second evaporation temperature being greater than 0 degree Celsius and less than a dew point temperature of an indoor environment; performing a second dehumidification operation based on a third evaporation temperature after the defrost operation is completed until an indoor humidity reaches a target humidity.

10. The method of claim 9, wherein, The method of performing frost prediction on the indoor evaporator to determine a defrost starting time comprises: determining an advanced defrosting time of the indoor evaporator according to the first evaporation temperature, the indoor humidity and a supply air volume; determining a defrosting start time according to the advanced defrosting time and a preset defrosting time.

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