Air conditioner defrosting control method and device, air conditioning system and storage medium

Abstract

The application relates to an air conditioner defrosting control method applied to an air conditioning system of rail transit, each air conditioning system comprising two air conditioning units; the method comprises the following steps: acquiring the working modes of the two air conditioning units; acquiring the outdoor coil temperatures of the two air conditioning units under the condition that any one of the two air conditioning units is in a heating mode and the other air conditioning unit is in a ventilation mode; determining whether the corresponding air conditioning unit meets a defrosting condition based on the outdoor coil temperatures; under the condition that the defrosting condition is met, controlling the air conditioning unit in the ventilation mode to be switched to the heating mode and controlling the air conditioning unit in the heating mode to be switched to the ventilation mode, thereby defrosting the frosted condenser through the ventilation mode while ensuring the indoor temperature of the subway carriage, and solving the problem that, in the related art, defrosting needs to switch the air conditioner to the refrigeration mode, thereby reducing the comfort of passengers.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rail transit air conditioning technology, and in particular to an air conditioner defrosting control method and device, an air conditioning system, and a storage medium. BACKGROUND

[0002] In winter, the surface temperature of the evaporator of a rail transit air conditioning system may be lower than 0 degrees due to the low-temperature and high-humidity working condition environment, causing the moisture in the air to frost on the air side of the evaporator. Frosting blocks the evaporator, causing the air flow to decrease and the heat exchange efficiency to decrease, thereby reducing the heating capacity and operating efficiency of the air conditioner. The existing defrosting method mainly changes the working mode of the air conditioning system from heating to cooling, changes the direction of the refrigerant cycle, and changes the evaporator into a condenser to defrost. However, this defrosting method requires the air conditioner to be switched to cooling mode, which reduces the supply air temperature and greatly affects the comfort of passengers.

[0003] Currently, there is no effective solution to the problem of defrosting requiring the air conditioner to be switched to cooling mode and reducing passenger comfort in the related art. SUMMARY

[0004] An air conditioner defrosting control method, device, air conditioning system, and storage medium are provided in the present embodiment to solve the problem of defrosting requiring the air conditioner to be switched to cooling mode and reducing passenger comfort in the related art.

[0005] In a first aspect, an air conditioner defrosting control method is provided in the present embodiment, applied to an air conditioning system of rail transit, the rail transit including a plurality of air conditioning systems, each of the air conditioning systems including two air conditioning units, and the method including:

[0006] obtaining the working modes of the two air conditioning units;

[0007] in a case where any one of the two air conditioning units is in a heating mode and the other air conditioning unit is in a ventilation mode, obtaining the outdoor coil temperature of the two air conditioning units;

[0008] determining whether the corresponding air conditioning unit meets a defrosting condition based on the outdoor coil temperature;

[0009] in a case where the defrosting condition is met, controlling the air conditioning unit in the ventilation mode to switch to the heating mode and controlling the air conditioning unit in the heating mode to switch to the ventilation mode.

[0010] In some embodiments, determining whether the corresponding air conditioning unit meets the defrosting condition based on the outdoor coil temperature includes:

[0011] determining whether the outdoor coil temperature is lower than a first preset temperature;

[0012] In a case where the outdoor coil temperature is lower than the first preset temperature, it is determined that the corresponding air conditioning unit satisfies the defrosting condition.

[0013] In some embodiments, the determining whether the corresponding air conditioning unit satisfies the defrosting condition based on the outdoor coil temperature comprises:

[0014] determining whether a duration that the outdoor coil temperature is lower than the first preset temperature is greater than a first preset time;

[0015] In a case where the duration is greater than the first preset time, it is determined that the corresponding air conditioning unit satisfies the defrosting condition.

[0016] In some embodiments, after the obtaining the outdoor coil temperatures of the two air conditioning units, the air conditioning defrosting control method further comprises:

[0017] obtaining a first indoor temperature at a current time;

[0018] determining whether a heating time required to reach a second preset temperature is greater than a second preset time based on the second preset temperature and the first indoor temperature;

[0019] In a case where the heating time is greater than the second preset time, controlling the air conditioning unit in the ventilation mode to switch to the heating mode and controlling the air conditioning unit in the heating mode to switch to the ventilation mode.

[0020] In some embodiments, the determining whether the heating time required to reach the second preset temperature is greater than the second preset time based on the second preset temperature and the first indoor temperature comprises:

[0021] obtaining a second indoor temperature at a historical time;

[0022] In a case where a temperature difference between the first indoor temperature and the second indoor temperature is less than a temperature difference between the second preset temperature and the first indoor temperature, it is determined that the heating time is greater than the second preset time, wherein the second preset time is determined based on an interval between the obtaining times of the second indoor temperature and the first indoor temperature.

[0023] In some embodiments, the controlling the air conditioning unit in the ventilation mode to switch to the heating mode and controlling the air conditioning unit in the heating mode to switch to the ventilation mode comprises:

[0024] controlling the air conditioning unit in the ventilation mode to switch to the heating mode;

[0025] after a third preset time elapses, controlling the air conditioning unit in the heating mode to switch to the ventilation mode.

[0026] In a second aspect, an air conditioner defrosting control device is provided in the embodiments. The air conditioner defrosting control device is applied to an air conditioning system of rail transit. The rail transit includes a plurality of air conditioning systems. Each of the air conditioning systems includes two air conditioner units. The air conditioner defrosting control device includes:

[0027] A first obtaining module is configured to obtain working modes of the two air conditioner units.

[0028] A second obtaining module is configured to obtain outdoor coil temperatures of the two air conditioner units when any one of the two air conditioner units is in a heating mode and the other air conditioner unit is in a ventilation mode.

[0029] A first determining module is configured to determine whether a corresponding air conditioner unit meets a defrosting condition based on the outdoor coil temperatures.

[0030] A first control module is configured to control the air conditioner unit in the ventilation mode to switch to the heating mode and control the air conditioner unit in the heating mode to switch to the ventilation mode when the defrosting condition is met.

[0031] In a third aspect, an air conditioning system applied to rail transit is provided in the embodiments. The air conditioning system includes two air conditioner units and an air conditioner defrosting control device for controlling working modes of the two air conditioner units, as described in the second aspect.

[0032] In some embodiments, the air conditioner units include condensers. The air conditioning system further includes a condenser fan. The condensers share the condenser fan.

[0033] In a fourth aspect, a computer readable storage medium is provided in the embodiments. The computer readable storage medium stores a computer program. The computer program is executed by a processor to implement steps of the air conditioner defrosting control method described in the first aspect.

[0034] Compared with related technologies, the air conditioner defrosting control method provided in the embodiments determines whether the air conditioner units are in a semi-warm working mode by obtaining working modes of the two air conditioner units. The method determines whether the condensers of the corresponding air conditioner units have frost by obtaining outdoor coil temperatures of the two air conditioner units in the semi-warm working mode and determining whether the corresponding air conditioner units meet a defrosting condition based on the outdoor coil temperatures. The method controls the air conditioner unit in the ventilation mode to switch to the heating mode and controls the air conditioner unit in the heating mode to switch to the ventilation mode when the defrosting condition is met. The indoor temperature of the subway car is ensured by the turn-to-heat of the two air conditioner units. The frost on the condensers is removed by the ventilation mode. The entire working process does not need to switch the air conditioner units to the refrigeration mode. The problem that the air conditioner needs to be switched to the refrigeration mode for defrosting in related technologies and the passenger comfort is reduced is solved.

[0035] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0037] Figure 1 This is a hardware structure block diagram of an air conditioning system according to an embodiment of this application, including two air conditioning units;

[0038] Figure 2 This is a flowchart of an air conditioning defrosting control method according to an embodiment of this application;

[0039] Figure 3 This is a flowchart illustrating the process of determining the heating time of the air conditioning unit for semi-warm ventilation defrosting according to an embodiment of this application;

[0040] Figure 4 This is a schematic diagram illustrating the relationship between heating time and indoor temperature changes in an embodiment of this application;

[0041] Figure 5 This is a flowchart of an air conditioner defrosting control method according to a preferred embodiment of this application;

[0042] Figure 6 This is a structural block diagram of an air conditioning defrosting control device according to an embodiment of this application. Detailed Implementation

[0043] To better understand the purpose, technical solution, and advantages of this application, the application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0044] Unless otherwise defined, technical terms or scientific terms used in the present application shall have the same meaning as those commonly understood by a person of ordinary skill in the art to which the present application belongs. In the present application, the terms "one", "a", "an", "the", "these", and similar words do not indicate a quantity restriction, and they can be singular or plural. In the present application, the terms "include", "contain", "have", and any variants thereof are intended to cover non-exclusive inclusion; for example, a process, method, and system, product or device including a series of steps or modules (units) are not limited to the listed steps or modules (units), but can include steps or modules (units) not listed, or can include other steps or modules (units) inherent to the process, method, product or device. In the present application, the terms "connect", "connected", "coupled" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. In the present application, "multiple" means two or more. The term "and / or" describes the association between the associated objects, which means that there can be three relationships, for example, "A and / or B" can mean that A exists alone, A and B exist together, and B exists alone. Generally, the character " / " represents an "or" relationship between the associated objects. In the present application, the terms "first", "second", "third", and the like are only used to distinguish similar objects, and do not represent a specific order of the objects.

[0045] The method embodiments provided in the present embodiment are applied to the air conditioning system of rail transit, and can be applied to the air conditioning system of a subway. The subway includes multiple carriages, and each carriage is generally independently configured with an air conditioning system. The number of air conditioning systems configured for each carriage can be two. In the present embodiment, each air conditioning system includes two air conditioning units and an air conditioning controller or control terminal, a computer or similar computing device for controlling the working mode of the air conditioning units. The method embodiments provided in the present embodiment can be executed in the air conditioning controller, control terminal, computer or similar computing device of the air conditioning system of rail transit, for example, in the air conditioning controller in the present embodiment. The air conditioning controller or other terminal, computer, etc. running the method embodiments can include one or more processors (the processor can include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA) and a memory for storing data, and a transmission device for communication function. Optionally, it can also include an input and output device. The memory can be used to store a computer program, for example, a software program of application software and modules, such as a computer program corresponding to the air conditioning defrosting control method in the present embodiment. The processor executes the computer program stored in the memory, thereby executing various functional applications and data processing, that is, realizing the above method.

[0046] The memory can include high-speed random access memory and can also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory can further include memory that is remotely located with respect to the processor, which can be connected to the air conditioning controller, or other terminal, computer, etc. via a network. Examples of the network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0047] The transmission device is used to receive or send data via a network. The specific example of the network can include a wireless network provided by a communication provider of the air conditioning controller, or other terminal, computer, etc. In one example, the transmission device includes a network adapter (NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device can be a radio frequency (RF) module, which is used to communicate with the Internet in a wireless manner.

[0048] Figure 1 is a hardware structure block diagram of two air conditioning units of one air conditioning system in the embodiment. As shown in Figure 1 , each air conditioning unit mainly includes a gas-liquid separator 11, a compressor 12, a four-way valve 13, an evaporator 14, an evaporative fan 15, an electronic expansion valve 16, a condenser 17, a condensing fan 18, and the like. Those skilled in the art can understand that Figure 1 the connection shown is only schematic, which does not limit the constitution of the air conditioning unit. For example, other components can also be included in the connection passage of the air conditioning unit, the evaporative fan 15, the condensing fan 18, and the like can also include more or less number, or each component has a different configuration from Figure 1 . Figure 1

[0049] Each air conditioning unit can be started and stopped and changed in working mode independently. According to actual needs, the working mode of the air conditioning system can be divided into half cold, full cold, half warm, full warm, and ventilation operation. In the half cold or half warm mode, one of the two air conditioning units of the air conditioning system is in the refrigeration or heating mode, and the other air conditioning unit is in the ventilation mode, in which the refrigerant circulation of the air conditioning unit is stopped. It should be noted that the condensing fans of the two air conditioning units in the embodiment are shared, so as long as one air conditioning unit performs refrigeration or heating, the corresponding condensing fans of the two air conditioning units are normally operated. In the case that the subway train stops running, the air conditioning unit can be in a shutdown state.

[0050] ​In the heating mode, the refrigerant in the gas-liquid separator 11 is discharged by the compressor 12 into the evaporator 14 (acting as a condenser in the heating mode) through the four-way valve 13, and the heat released when the refrigerant vapor condenses heats the indoor air to achieve the purpose of indoor heating. The condensed liquid refrigerant is throttled by the electronic expansion valve 16 and becomes low-temperature and low-pressure refrigerant into the condenser 17 (acting as an evaporator in the heating mode), absorbs external heat and evaporates, and the evaporated vapor refrigerant enters the gas-liquid separator 11 through the four-way valve 13 to complete the heating cycle. In the cooling mode, the flow direction of the refrigerant in the air conditioning unit is opposite to that in the heating cycle. The high-pressure vapor discharged by the compressor 12 flows into the condenser 17 through the four-way valve 13 and releases heat, and the condensed liquid refrigerant is throttled by the electronic expansion valve 16 and then enters the evaporator 14, absorbs the heat of the indoor air, and reduces the indoor temperature. The evaporated vapor refrigerant enters the gas-liquid separator 11 through the four-way valve 13 to complete the cooling cycle.

[0051] In this embodiment, a defrosting control method of an air conditioner is provided, Figure 2 is a flow chart of the defrosting control method of the air conditioner of this embodiment, as shown in the figure, the flow includes the following steps: Figure 2

[0052] Step S201, obtaining the working mode of the two air conditioning units.

[0053] Step S202, obtaining the outdoor coil temperature of the two air conditioning units when either of the two air conditioning units is in the heating mode and the other is in the ventilation mode.

[0054] The heat exchange performance of the subway air conditioning system is usually designed according to the refrigeration working condition, and the heating capacity often exceeds the actual demand, and in general cases, the half-warm mode can meet the heating demand. Half-warm mode, that is, one of the two air conditioning units is in the heating mode and the other is in the ventilation mode. The defrosting control method of the air conditioner of this embodiment can be operated in the half-warm mode. After determining that the two air conditioning units are in the half-warm mode, the outdoor coil temperature of the air conditioning unit is obtained. Each air conditioning unit includes at least one outdoor coil, the outdoor coil is in communication with the inlet of the condenser 17, the outdoor coil is a flow channel of the refrigerant, and the temperature of the outdoor coil reflects the temperature of the refrigerant at the inlet of the condenser 17.

[0055] Step S203, determining whether the corresponding air conditioning unit meets the defrosting condition based on the outdoor coil temperature.

[0056] ​When the ambient temperature is low and the humidity is large, and the air conditioning unit is in the heating mode, the refrigerant entering the condenser through the outdoor coil is low-temperature refrigerant throttled by the electronic expansion valve 16, and the temperature thereof can be below zero degrees, causing the moisture in the outdoor air to frost on the condenser or coil. The severity of frosting is related to the temperature of the refrigerant and the ambient temperature and humidity. A temperature sensor can be installed on the outdoor coil to determine the frosting condition of the condenser 17 surface according to the temperature of the refrigerant in the outdoor coil obtained by the temperature sensor.

[0057] Step S204, in the case where the defrosting condition is met, the air conditioning unit in the ventilation mode is switched to the heating mode, and the air conditioning unit in the heating mode is switched to the ventilation mode.

[0058] When the condenser surface needs to be defrosted by the outdoor coil temperature, the two air conditioning units are alternately operated in the heating mode and the ventilation mode by switching the operating modes of the two air conditioning units. In the ventilation mode, the refrigerant circulation stops flowing, and the temperature of the refrigerant in the corresponding condenser 17 rises, which can reduce and defrost the frost to a certain extent. In addition, due to the shared condenser fan 18, the frost on the condenser 17 can be defrosted under the action of the natural wind in the ventilation mode.

[0059] Through the above steps S201 to S204, by obtaining the operating modes of the two air conditioning units, it is determined whether the air conditioning unit is in the semi-warm operating mode; by obtaining the outdoor coil temperature of the two air conditioning units in the semi-warm operating mode and determining whether the corresponding air conditioning unit meets the defrosting condition based on the outdoor coil temperature, it is determined whether the condenser of the corresponding air conditioning unit has frosted; in the case where the defrosting condition is met, the air conditioning unit in the ventilation mode is switched to the heating mode, and the air conditioning unit in the heating mode is switched to the ventilation mode, and the indoor temperature of the subway car is ensured by the turn-to-heat of the two air conditioning units, and the frosted condenser is defrosted, and the entire working process does not need to switch the air conditioning unit to the refrigeration mode, solving the problem of reducing passenger comfort in the related art that the air conditioning needs to be switched to the refrigeration mode for defrosting.

[0060] In some embodiments, a specific process for determining whether the air conditioning unit meets the defrosting condition is involved, which includes the following steps:

[0061] Step S11, determining whether the outdoor coil temperature is lower than a first preset temperature.

[0062] When the outdoor coil temperature of the air conditioning unit is lower than the first preset temperature, it indicates that the air conditioning condenser temperature corresponding to the outdoor coil is low, and there is frost, which needs to be defrosted. Here, the temperature threshold can be used for judgment as a prerequisite for starting defrosting in the semi-warm ventilation mode. The first preset temperature can be adjusted according to the actual operation, which is mainly related to the local winter temperature and humidity environment. Generally, it can be taken as -7℃ to -12℃.

[0063] Step S12, in the case that the outdoor coil temperature is lower than the first preset temperature, it is determined that the corresponding air conditioning unit meets the defrosting condition.

[0064] Through the above steps S11 to S12, the embodiment gives the specific conditions and judgment method for starting defrosting in the semi-warm ventilation mode by taking whether the outdoor coil temperature is lower than the first preset temperature as the criterion for meeting the defrosting condition, which provides the necessary judgment basis for defrosting in the semi-warm ventilation mode.

[0065] In some embodiments, a process for confirming the outdoor coil temperature is also involved. The process includes the following steps:

[0066] Step S21, it is determined whether the duration that the outdoor coil temperature is lower than the first preset temperature is greater than the first preset time.

[0067] In order to avoid outdoor coil temperature reading error, or the read temperature being at the critical value of the first preset temperature, causing the air conditioning unit to repeatedly enter or exit the defrosting state, the outdoor coil temperature needs to be confirmed. Generally, the temperature sensor reading error problem can be avoided by confirming the temperature sensor through multiple readings; the duration that the outdoor coil temperature is lower than the first preset temperature can also be used to determine whether defrosting can be performed. In this embodiment, the duration that the outdoor coil temperature is lower than the first preset temperature is obtained by reading the outdoor coil temperature to determine whether the defrosting condition is met. The duration can be set to 60 seconds, or it can be adjusted according to actual needs. The method of obtaining the duration can be to read the sensor temperature multiple times within the first preset time, and if the sensor temperature value is lower than the first preset temperature, it is determined that the duration is greater than the first preset time.

[0068] Step S22, in the case that the duration is greater than the first preset time, it is determined that the corresponding air conditioning unit meets the defrosting condition.

[0069] Through the above steps S21 to S22, the embodiment takes the duration that the outdoor coil temperature is lower than the first preset temperature as a supplementary criterion for meeting the defrosting condition, in order to avoid outdoor coil temperature reading error, or the read temperature cannot be stably maintained below the first preset temperature, thereby avoiding the air conditioning unit repeatedly switching between entering and exiting the semi-warm ventilation defrosting state, affecting the heating effect and defrosting effect of the air conditioning unit.

[0070] In some embodiments, to avoid frequent start-stop of the air conditioner compressor, the process of determining the heating time before the air conditioning unit performs semi-warm ventilation defrosting is also involved. Figure 3 is a flowchart of the process of determining the heating time of the air conditioning unit for semi-warm ventilation defrosting in this embodiment, as shown in the figure, the process includes the following steps: Figure 3

[0071] Step S301: Obtain the first indoor temperature at the current time.

[0072] Taking the subway air conditioning system as an example, the heating mode of the air conditioning unit is to preset a temperature as the target value of heating, when the environmental temperature in the subway car reaches the target value of heating, the air conditioning unit stops heating and the compressor stops running. In the case of semi-warm ventilation defrosting, the compressors of two air conditioning units need to work alternately. When one air conditioning unit is just started, if the environmental temperature in the car reaches the target temperature soon, the air conditioning unit will stop running soon. In order to prevent the phenomenon of frequent start-stop of the compressor in this case, before the two air conditioning units switch the working mode, the heating time required from the current indoor temperature to the second preset temperature as the target value of heating needs to be determined. If the heating time is too short, the working mode of the two air conditioning units should not be switched. The first indoor temperature in this embodiment refers to the indoor environmental temperature of the subway car at the current time.

[0073] Step S302: Determine whether the heating time required to reach the second preset temperature is greater than the second preset time based on the second preset temperature and the first indoor temperature.

[0074] The second preset temperature refers to the target temperature of heating of the subway car, after reaching this temperature, the air conditioning unit will stop heating. According to the difference between the first indoor temperature and the second preset temperature, it is determined how much heating time is needed to reach the second preset temperature under the current heating condition, and this heating time determines the working time of the compressor in the heating mode after the air conditioning unit switches the working mode. The second preset time is the criterion for determining whether the working time of the compressor is too short, if the working time is less than the second preset time, it is determined that the working time of the compressor is too short and the start-stop is frequent, so the working mode of the two air conditioning units should not be switched. The second preset time is 3 minutes in this embodiment, which can be adjusted according to actual needs.

[0075] The estimation of the heating time can be determined by the temperature change rate of the indoor environmental temperature in the historical time, and the temperature difference between the second preset temperature and the first indoor temperature.

[0076] ​Step S303, in the case that the heating time is greater than the second preset time, the air conditioning unit in the ventilation mode is switched to the heating mode, and the air conditioning unit in the heating mode is switched to the ventilation mode.

[0077] In the case that the heating time is greater than the second preset time, it is indicated that the working mode is switched, and the compressor working time in the heating mode is normal, which will not cause the frequent start-stop problem, so the working modes of the two air conditioning units can be switched.

[0078] Through the above steps S301 to S303, by estimating the heating time of the compressor before the working mode is switched, in the case that the heating time is greater than the second preset time, it is determined that the compressor will not have the frequent start-stop phenomenon after the working mode is switched, and the working mode switching of the two air conditioning units can be performed. In the case that the heating time is less than the second preset time, the switching is not allowed to be performed to avoid the problem of frequent start-stop of the compressor and ensure the reliability of the compressor operation.

[0079] In some embodiments, a specific method for determining the heating time is involved. The method includes the following steps:

[0080] Step S31, a second indoor temperature at a historical time is obtained.

[0081] The second indoor temperature is the temperature of the indoor environment of the subway car at a time before the current time. Through the second indoor temperature, the first indoor temperature, and the interval time between the historical time and the current time, the change of the temperature of the indoor environment of the subway car can be determined. It should be noted that during the interval time, the air conditioning unit should continue to operate in the half-warm mode. If the air conditioning unit operates in the full-warm or other working mode during the interval time, the temperature change rate of the indoor temperature is different from that in the half-warm mode, and the temperature change in the half-warm mode cannot be predicted according to the temperature change during the interval time. In order to ensure the stability of the temperature sampling, the average temperature in a period of time can be collected as the first indoor temperature and the second indoor temperature.

[0082] Step S32, in the case that the temperature difference between the first indoor temperature and the second indoor temperature is less than the temperature difference between the second preset temperature and the first indoor temperature, it is determined that the heating time is greater than the second preset time, wherein the second preset time is determined based on the interval time between the acquisition time of the second indoor temperature and the first indoor temperature.

[0083] Since the working mode of the air conditioning unit is unchanged, for the convenience of understanding, it can be considered that the rate of change of the indoor temperature with time is unchanged. It is assumed that the time interval for obtaining the second indoor temperature and the first indoor temperature is t1, the second preset time is t2, the heating time required to reach the second preset temperature from the current time is t3. The temperature difference between the first indoor temperature and the second indoor temperature is ΔT1, the temperature difference between the indoor temperature after running for the second preset time from the current time and the first indoor temperature is ΔT2, and the temperature difference between the second preset temperature and the first indoor temperature is ΔT3. In this embodiment, t2 and t1 can be set to be equal, i.e. t1 is equal to the second preset time.

[0084] Figure 4 is a schematic diagram of the relationship between the heating time of this embodiment and the change of the indoor temperature, as Figure 4 shown, in the case of t1=t2, ΔT1=ΔT2 can be determined. Therefore, when ΔT1<ΔT3, it can be deduced that t3>t2, i.e. in the case where the time interval for obtaining the second indoor temperature and the first indoor temperature is equal to the second preset time, if the temperature difference between the first indoor temperature and the second indoor temperature is less than the temperature difference between the second preset temperature and the first indoor temperature, the heating time required to reach the second preset temperature from the current time is greater than the second preset time. In this case, after switching the working mode, the indoor temperature has not reached the second preset temperature after the air conditioner compressor in the heating mode works for the second preset time, so the compressor will not be stopped. That is, as long as the difference between the current first indoor temperature and the second indoor temperature before the second preset time is less than the difference between the second preset temperature and the current first indoor temperature (i.e. first indoor temperature-second indoor temperature before the second preset time < second preset temperature-first indoor temperature), the running time of the compressor of the air conditioning unit in the heating mode after switching the mode is ensured to be longer than the second preset time, which is beneficial to avoid frequent starting and stopping of the compressor.

[0085] Through the above steps S31 to S32, by obtaining the second indoor temperature before the second preset time and judging according to the temperature difference between the first indoor temperature and the second indoor temperature and the temperature difference between the second preset temperature and the first indoor temperature, it is determined whether the heating time (i.e. the running time of the compressor) is greater than the second preset time, so as to determine whether the compressor is frequently started and stopped after switching the working mode, thus giving a specific method for determining the working time of the compressor. The method is simple and fast, and does not need to calculate the historical temperature change rate of the indoor temperature to determine whether the heating time of the compressor after switching the working mode is greater than the second preset time, so as to ensure that the compressor will not be frequently started and stopped, and ensure the reliability of the working of the air conditioning unit.

[0086] In some embodiments, a specific process for switching the working mode of two air conditioning units is involved. The process includes the following steps:

[0087] Step S41, control the air conditioning unit in ventilation mode to switch to heating mode;

[0088] Step S42, after delaying for the third preset time, control the air conditioning unit in heating mode to switch to ventilation mode.

[0089] The compressor needs a certain time from starting to preliminary stable operation. If the two air conditioning units switch the working mode at the same time, the heating effect of the air conditioning unit will be affected during the time before stable operation, and the comfort of the passengers will be affected. To avoid this situation, the third preset time is set as the delay time to delay the switching of the air conditioning unit originally in heating mode. That is, during the third preset time, both air conditioning units are in heating state to ensure the heating effect of the subway car. The third preset time can be set according to actual conditions, and in the embodiment, it is set to 30s-90s.

[0090] Through the above steps S41-S42, the air conditioning unit originally in ventilation mode is switched to heating mode first to ensure the heating effect of the subway car, and then the air conditioning unit originally in heating mode is switched to ventilation mode after delaying for the third preset time to ensure the heating effect of the subway car and the comfort of the passengers.

[0091] The preferred embodiment will be described and explained below.

[0092] Figure 5 The flowchart of the air conditioning defrosting control method of the preferred embodiment. As shown in Figure 5 The air conditioning defrosting control method includes the following steps:

[0093] Step S501, obtain the working mode of the two air conditioning units;

[0094] Step S502, determine that any one of the two air conditioning units is in heating mode and the other air conditioning unit is in ventilation mode;

[0095] Step S503, under the condition of meeting the above conditions, obtain the outdoor coil temperature of the two air conditioning units;

[0096] Define the outdoor coil temperature corresponding to the outdoor coil as Tco-x. As described above, each car can be configured with two independent air conditioning systems, and each air conditioning system includes two air conditioning units. x can be used to distinguish the outdoor coil temperature of different air conditioning units, such as the outdoor coil temperature can be set as Tco-11, Tco-12, Tco-21, Tco-22, wherein the first digit of x represents the air conditioning system number, and the second digit represents the air conditioning unit number under the corresponding air conditioning system.

[0097] Step S504, determine whether any outdoor coil temperature Tco-x is less than the first preset temperature T1, and the duration t of less than T1 is greater than the first preset time t1?

[0098] T1 is the defrosting judgment target temperature value, which can be adjusted according to the actual operation, and is related to the local winter temperature and humidity environment, and can be taken as-7℃ to-12℃. T1 is the defrosting judgment target time value, which is mainly set to avoid misjudgment, and is usually set to 60s, and can also be adjusted according to actual requirements.

[0099] Step S505, in the case of meeting the above conditions, the first indoor temperature at the current time is obtained;

[0100] Step S506, the second indoor temperature at the historical time is obtained, wherein the time interval between the current time and the historical time is equal to the second preset time t2;

[0101] The second preset time t2 can be set to three minutes.

[0102] Step S507, determine whether the temperature difference △T1 of the first indoor temperature and the second indoor temperature is less than the temperature difference △T2 of the second preset temperature and the first indoor temperature;

[0103] Specifically, △T1 = current time indoor temperature-3 minutes ago indoor temperature, and the temperature can be taken as the average temperature value of 1 minute;

[0104] △T2 = second preset temperature (i.e. heating target temperature)-current time indoor temperature.

[0105] In the case of △T1 <△T2, it can be ensured that the compressor running time after switching is more than 3 minutes, avoiding the compressor frequent start-stop in a short time.

[0106] Step S508, in the case of meeting the above conditions, the air conditioning unit in the ventilation mode is switched to the heating mode;

[0107] Step S509, after delaying the third preset time t3, the air conditioning unit in the heating mode is switched to the ventilation mode.

[0108] The third preset time t3, i.e. the delay stop time, can be set to 30S-90S according to the actual situation.

[0109] Through the steps S501-S509, in the case that the air conditioning unit is determined to be in the semi-warm working mode, whether the outdoor coil temperature of any one of the two air conditioning units is less than the first preset temperature and the duration is greater than the first preset time are obtained to determine the correctness and stability of the outdoor coil temperature, so as to determine whether the air conditioning unit meets the defrosting condition; in the case that the defrosting condition is met, whether the temperature difference between the first indoor temperature and the second indoor temperature is less than the temperature difference between the second preset temperature and the first indoor temperature is determined to determine that the running time of the compressor after switching exceeds the second preset time, so as to avoid frequent start and stop of the compressor; then the air conditioning unit originally in the ventilation mode is switched to the heating mode, and the air conditioning unit originally in the heating mode is switched to the ventilation mode after a delay of the third preset time, so as to avoid that the unstable work of the just started compressor affects the heating effect. The indoor temperature of the subway car is ensured through the turn-by-turn heating of the two air conditioning units, and the defrosted condenser is defrosted through the ventilation mode, and the whole working process does not need to switch the air conditioning unit to the refrigeration mode, thereby solving the problem in the related art that the air conditioning needs to be switched to the refrigeration mode for defrosting, and reducing the comfort of passengers.

[0110] It should be noted that the steps shown in the above flow or the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that here.

[0111] In the embodiment, an air conditioning defrosting control device is also provided, which is applied to a subway heat pump air conditioning system. The air conditioning defrosting control device is used to implement the above-mentioned embodiments and preferred embodiments, which have been described above. The terms "module", "unit", "sub-unit" and the like used below can be a combination of software and / or hardware that can implement a predetermined function. Although the system described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware is also possible and is conceived.

[0112] Figure 6 is a structural block diagram of the air conditioning defrosting control device of the embodiment, as Figure 6 shown, the air conditioning defrosting control device comprises a first acquisition module 61, a second acquisition module 62, a first determination module 63 and a first control module 64.

[0113] The first acquisition module 61 is configured to acquire the working modes of the two air conditioning units.

[0114] The second acquisition module 62 is configured to acquire the outdoor coil temperatures of the two air conditioning units in the case that any one of the two air conditioning units is in the heating mode and the other air conditioning unit is in the ventilation mode.

[0115] The first determination module 63 is configured to determine whether the corresponding air conditioning unit meets the defrosting condition based on the outdoor coil temperature.

[0116] The first control module 64 is configured to control the air conditioning unit in the ventilation mode to switch to the heating mode and control the air conditioning unit in the heating mode to switch to the ventilation mode when the defrosting condition is met.

[0117] The air conditioning defrosting control device provided in the embodiment acquires the working mode of the air conditioning unit through the first acquisition module 61, acquires the outdoor coil temperature of the two air conditioning units in the semi-warm working mode through the second acquisition module 62, determines whether the corresponding air conditioning unit meets the defrosting condition through the first determination module 63, judges whether the corresponding air conditioning unit has been frosted, controls the air conditioning unit in the ventilation mode to switch to the heating mode and controls the air conditioning unit in the heating mode to switch to the ventilation mode through the first control module 64 when the defrosting condition is met, ensures the indoor temperature of the subway car through the turn-to-heat of the two air conditioning units, and achieves the purpose of defrosting. The whole working process does not need to switch the air conditioning unit to the refrigeration mode, and the problem that the air conditioning needs to be switched to the refrigeration mode for defrosting in the related art and the passenger comfort is reduced is solved.

[0118] It should be noted that each of the above modules can be a function module or a program module, and can be implemented by software or hardware. For the modules implemented by hardware, each of the above modules can be located in the same processor, or each of the above modules can be located in different processors in any combination.

[0119] In the embodiment, an air conditioning system applied to rail transit is also provided, each air conditioning system including two air conditioning units and an air conditioning defrosting control device for controlling the working mode of the two air conditioning units through any one of the air conditioning defrosting control methods provided in the above embodiments.

[0120] The air conditioning system applied to rail transit provided in the embodiment controls whether the air conditioning unit meets the defrosting condition in the semi-warm ventilation working mode through the air conditioning defrosting control device, controls the two air conditioning units to be in the heating mode and the ventilation mode in turn when the defrosting condition is met, ensures the indoor temperature of the car, and achieves the purpose of defrosting. The whole working process does not need to switch the air conditioning unit to the refrigeration mode, and the problem that the air conditioning needs to be switched to the refrigeration mode for defrosting in the related art and the passenger comfort is reduced is solved. In addition, in combination with the air conditioning defrosting control method provided in the above embodiments, a storage medium can also be provided in the embodiment to be implemented. The storage medium stores a computer program, and the computer program is executed by a processor to implement any one of the air conditioning defrosting control methods in the above embodiments.

[0121] It should be understood that the detailed description and specific examples described herein are intended for purposes of illustration only and are not intended to limit the scope of the present application. Consequently, all other embodiments that would be apparent to one of ordinary skill in the art from the preceding description and drawings are intended to be within the scope and spirit of the present application.

[0122] Obviously, the drawings described herein are only a few examples of implementations of the present application and can be applied to other similar situations without creative work by one of ordinary skill in the art. In addition, it can be understood that although the work done in the development process can be complex and long, certain design, manufacture or production changes made according to the technical content disclosed in the present application by one of ordinary skill in the art are only routine technical means and should not be regarded as insufficient disclosure of the present application.

[0123] The word "embodiment" in the present application refers to the specific features, structures or characteristics described in conjunction with the embodiments can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor does it mean independence or alternatives to other embodiments. It can be clearly or implicitly understood by one of ordinary skill in the art that the embodiments described in the present application can be combined with other embodiments without conflict.

[0124] The above-described embodiments only express several implementations of the present application, which are described in detail and in detail, but should not be construed as limiting the scope of patent protection. It should be noted that for one of ordinary skill in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. An air conditioning defrosting control method, applied to an air conditioning system of rail transit, wherein the rail transit includes multiple air conditioning systems, each of the air conditioning systems including two air conditioning units, characterized in that, The method includes: Obtain the operating modes of the two air conditioning units; When one of the two air conditioning units is in heating mode and the other is in ventilation mode, the outdoor coil temperature of the two air conditioning units and the first indoor temperature at the current moment are obtained. Determine whether the outdoor coil temperature is lower than the first preset temperature; if so, determine that the corresponding air conditioning unit meets the defrosting conditions. If the defrosting conditions are met, based on the second preset temperature and the first indoor temperature, determine whether the heating time required to reach the second preset temperature is greater than the second preset time; if so, control the air conditioning unit in ventilation mode to switch to heating mode, and control the air conditioning unit in heating mode to switch to ventilation mode.

2. The method according to claim 1, characterized in that, The step of determining whether the corresponding air conditioning unit meets the defrosting conditions based on the outdoor coil temperature includes: Determine whether the duration during which the outdoor coil temperature is lower than the first preset temperature is greater than the first preset time; If the duration is greater than the first preset time, the corresponding air conditioning unit is determined to meet the defrosting conditions.

3. The method according to claim 1, characterized in that, The step of determining whether the heating time required to reach the second preset temperature is greater than the second preset time based on the second preset temperature and the first indoor temperature includes: Obtain the second indoor temperature at a historical moment; If the temperature difference between the first indoor temperature and the second indoor temperature is less than the temperature difference between the second preset temperature and the first indoor temperature, the heating time is determined to be greater than the second preset time, wherein the second preset time is determined based on the time interval between the acquisition of the second indoor temperature and the first indoor temperature.

4. The method according to any one of claims 1-3, characterized in that, The control of switching the air conditioning unit from ventilation mode to heating mode includes: Control the air conditioning unit in ventilation mode to switch to heating mode; After a third preset time delay, the air conditioning unit in heating mode is switched to ventilation mode.

5. An air conditioning defrosting control device, applied to an air conditioning system of rail transit, said rail transit including multiple air conditioning systems, each of said air conditioning systems including two air conditioning units, characterized in that, The air conditioning defrosting control device includes: The first acquisition module is used to acquire the operating modes of the two air conditioning units; The second acquisition module is used to acquire the outdoor coil temperature of the two air conditioning units and the first indoor temperature at the current moment when one of the two air conditioning units is in heating mode and the other air conditioning unit is in ventilation mode. The first determining module is used to determine whether the outdoor coil temperature is lower than the first preset temperature; if so, it determines that the corresponding air conditioning unit meets the defrosting conditions. The first control module is used to determine, based on the second preset temperature and the first indoor temperature, whether the heating time required to reach the second preset temperature is greater than the second preset time when the defrosting conditions are met; if so, control the air conditioning unit in ventilation mode to switch to heating mode, and control the air conditioning unit in heating mode to switch to ventilation mode.

6. An air conditioning system for rail transit, characterized in that, It includes two air conditioning units, and an air conditioning defrosting control device as described in claim 5 for controlling the operating mode of the two air conditioning units.

7. The air conditioning system according to claim 6, characterized in that: The air conditioning unit includes a condenser, and the air conditioning system also includes a condensing fan, with the condenser sharing the condensing fan.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the air conditioning defrosting control method according to any one of claims 1-4.

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