Double-cold-source air conditioning unit and control method

Abstract

The invention discloses a double-cold-source air conditioning unit and a control method, and relates to the technical field of machine room air conditioners, and the air conditioning unit comprises a chilled water system, a fluorine system and a temperature detection system; the chilled water system comprises a chilled water circulation loop and a chilled water coil pipe arranged on the chilled water circulation loop, and a control valve is further arranged on the chilled water circulation loop; the fluorine system comprises a compressor, a fluorine pump, an evaporator, a condenser and a throttling element, and the compressor, the fluorine pump, the evaporator, the condenser and the throttling element are connected to form a fluorine circulation loop of the fluorine system; the temperature detection system comprises a plurality of temperature sensors and is used for detecting the air supply temperature of the air conditioner unit, the water inlet temperature of the chilled water coil pipe and the air return temperature of the air conditioner unit. According to the invention, the temperature rise of the machine room caused by tedious manual switching and untimely system switching is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of computer room air conditioning, and in particular to a dual-cold-source air conditioning unit and a control method thereof. Background Art

[0002] Dual-cold-source air-conditioning units usually use a chilled water cooling system and a fluorine refrigeration system in parallel to provide sufficient cooling capacity for the data center to ensure the refrigeration reliability of the dual-cold-source air-conditioning system.

[0003] In the process of implementing the present invention, the inventors found that the prior art has at least the following problems:

[0004] When the chilled water cooling system as the main cooling mode fails, it is necessary to manually switch to the fluorine system as the backup cooling mode in time to ensure the temperature in the computer room; or after the chilled water cooling system returns to normal, it is necessary to manually switch the fluorine cooling system to the chilled water cooling mode. The above manual switching process is cumbersome and will cause the temperature in the computer room to rise rapidly, endangering the reliability of the computer room.

[0005] Therefore, in view of the above technical problems, how to avoid the increase of the temperature of the computer room caused by the untimely system switching is a technical problem that technical personnel in this field need to solve. Summary of the invention

[0006] The purpose of the present application is to provide a dual-cold source air-conditioning unit and a control method, which avoids the increase in room temperature caused by the cumbersome manual switching and the untimely system switching.

[0007] To achieve the above-mentioned purpose, the present application provides a dual-cold-source air-conditioning unit, including a chilled water system, a fluorine system, and a temperature detection system;

[0008] The chilled water system comprises a chilled water circulation loop and a chilled water coil arranged on the chilled water circulation loop, and the chilled water circulation loop is also provided with a control valve;

[0009] The fluorine system comprises a compressor, a fluorine pump, an evaporator, a condenser and a throttling element, wherein the compressor, the fluorine pump, the evaporator, the condenser and the throttling element are connected to form a fluorine circulation loop of the fluorine system;

[0010] The temperature detection system includes a plurality of temperature sensors, and the temperature detection system is used to detect the supply air temperature of the air conditioning unit, the water inlet temperature of the chilled water coil, and the return air temperature of the air conditioning unit.

[0011] Preferably, there are two groups of fluorine systems, and the evaporators in the two groups of fluorine systems are arranged front and back according to the return air direction, so that the return air from the machine room passes through the two evaporators in sequence and is supplied to the machine room through the indoor fan.

[0012] Preferably, the evaporator is an evaporation coil, and the chilled water coil corresponds to the evaporation coil in position, so that the return air from the machine room passes through the chilled water coil and the evaporation coil in sequence and then is delivered to the machine room.

[0013] A control method is applied to the above-mentioned dual cold source air conditioning unit, the control method comprising:

[0014] Determine whether an automatic switching mode signal is received when the air conditioning unit is running and selected, if so, the air conditioning unit automatically runs in a chilled water mode; if not, control the air conditioning unit to run in a manual switching mode;

[0015] When the air conditioning unit operates in the chilled water mode, the air conditioning unit automatically detects whether the chilled water system fails. If so, the air conditioning unit automatically switches to the fluorine mode; if not, the air conditioning unit continues to operate in the chilled water mode;

[0016] After the air-conditioning unit automatically switches to the fluorine mode, the air-conditioning unit automatically detects whether the fault of the chilled water system is eliminated. If so, the air-conditioning unit automatically switches to the chilled water mode; if not, it continues to operate the fluorine mode.

[0017] Preferably, when the air conditioning unit operates in the chilled water mode, the step of automatically detecting whether the chilled water system of the air conditioning unit is faulty comprises:

[0018] Determine whether the actual supply air temperature of the air-conditioning unit is higher than the preset supply air temperature. If not, the chilled water system is not faulty. If so, detect whether the control valve is faulty or at the maximum opening. If the control valve is faulty or at the maximum opening and lasts for a preset time, determine that the chilled water system is faulty.

[0019] Preferably, after the air conditioning unit automatically switches to the fluorine mode, it further includes:

[0020] Determine whether the water inlet temperature of the chilled water coil is higher than the return air temperature of the air conditioning unit, if so, control the opening of the control valve to be the minimum opening; if not, control the opening of the control valve to be the maximum opening;

[0021] The operating frequency of the compressor of the fluorine system is adjusted according to the heat exchange capacity of the current chilled water coil and the refrigeration demand of the computer room.

[0022] Preferably, the air conditioning unit automatically detects whether the fault of the chilled water system is eliminated, including:

[0023] When the compressor is controlled to operate at the lowest frequency, it is determined whether the actual supply air temperature of the air-conditioning unit is less than or equal to the preset supply air temperature. If so, the fault of the chilled water system is eliminated after the fluorine system runs for a preset time; if not, the fault of the chilled water system is not eliminated.

[0024] Preferably, after the fluorine system runs for a preset time and the fault of the chilled water system is eliminated, the method further comprises:

[0025] Controlling and closing the fluorine system and detecting the current opening of the control valve;

[0026] If the control valve is at the maximum opening, the chilled water mode is operated;

[0027] If the control valve is at the minimum opening, the machine room has no cooling demand and the air conditioning unit enters a standby state.

[0028] Preferably, when the air conditioning unit is in operation, the control valve is controlled to at least maintain a minimum opening in a non-closed state.

[0029] Preferably, when the air-conditioning unit operates in the chilled water mode, the opening of the control valve is adjusted according to the cooling demand of the machine room. After the opening of the control valve reaches the minimum opening and continues for a preset time, the machine room has no cooling demand and the air-conditioning unit enters standby mode.

[0030] Compared with the prior art, the technical solution provided by this application has at least the following beneficial effects:

[0031] The air conditioning unit of the present application can select an automatic switching mode, with the chilled water system as the main refrigeration mode. When the chilled water system fails, the air conditioning unit can automatically switch to the standby fluorine system refrigeration mode to meet the cooling demand of the machine room and prevent the temperature in the machine room from rising. At the same time, the air conditioning unit can identify whether the chilled water system has returned to normal. When the chilled water system has returned to normal, the air conditioning unit can automatically switch to the chilled water system, which can also prevent the temperature in the machine room from rising. The air conditioning unit avoids the tedious manual switching and the increase in the temperature of the machine room caused by the untimely system switching.

[0032] In addition, the air-conditioning unit of the present application can also select a manual mode. For a chilled water system that requires regular maintenance, the fluorine system refrigeration mode can be manually selected, and the chilled water mode can be switched back after the maintenance is completed. This is convenient and fast, and has a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0034] FIG1 is a schematic diagram of the principle of a dual cold source air conditioning unit provided in an embodiment of the present application;

[0035] FIG. 2 is a flowchart of a control method provided in an embodiment of the present application.

[0036] In the figure:

[0037] 1- compressor; 2- evaporator; 3- condenser; 4- fluorine pump; 5- fluorine circulation loop; 6- throttling element; 7- chilled water coil; 8- cooling unit; 9- chilled water circulation loop; 10- control valve. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] It should be noted that in this embodiment, the directions or positional relationships indicated by "upper", "lower", "front", "back", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present application. In addition, "first", "second", "third", and "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0040] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0041] As shown in FIG1 , in this embodiment, a dual-cold-source air-conditioning unit is provided. The air-conditioning unit includes a chilled water system, a fluorine system and a temperature detection system. The chilled water system serves as a main refrigeration system, and the fluorine system serves as a backup refrigeration system. When the chilled water system fails or requires maintenance, the backup fluorine system refrigeration can be enabled to avoid excessive temperature in the computer room.

[0042] The chilled water system includes a chilled water circulation loop 9 and a chilled water coil 7 disposed on the chilled water circulation loop 9. The circulating water can flow in the circulation loop, so that when the circulating water flows to the chilled water coil 7, it can exchange heat with the return air of the machine room, and after the return air of the machine room completes the heat exchange, it supplies air to the machine room. The chilled water system also includes a cooling unit 8, which is also disposed on the chilled water circulation loop 9. After the circulating water exchanges heat with the return air of the machine room, the temperature of the circulating water will increase. The circulating water with increased temperature can exchange heat at the cooling component and discharge the heat to the outdoor environment, so that it can flow to the chilled water coil 7 through the circulation loop again, realizing the circulating flow and heat exchange of the circulating water.

[0043] In addition, a control valve 10 is provided on the chilled water circuit, and the control valve 10 can control the flow of circulating water in the circulation circuit according to its opening size, thereby changing the heat exchange capacity of the chilled water coil 7. The control valve 10 can be an electromagnetic control valve, which can automatically adjust its opening and monitor its opening condition.

[0044] Among them, the cooling unit 8 can be an air-cooled cooling unit, a water-cooled cold zone unit, an evaporative cooling unit, etc., as long as it can ensure the cooling of the circulating water. They will not be described in detail here, and all fall within the protection scope of this application.

[0045] The fluorine system includes a compressor 1, a fluorine pump 4, an evaporator 2 and a condenser 3, etc. The compressor 1, the fluorine pump 4, the evaporator 2 and the condenser 3 are connected to form a fluorine circulation loop 5 of the fluorine system. Of course, the fluorine system also includes components such as a throttling element 6, a temperature and pressure sensor, etc. The throttling element 6 can be an electronic expansion valve, which will not be described here, and can refer to the prior art.

[0046] Among them, after the air-conditioning unit starts running, if there is a cooling demand in the computer room, at least one of the fluorine system and the chilled water system can provide cooling capacity to meet the cooling demand of the computer room.

[0047] The temperature detection system includes several temperature sensors, which can be arranged on the air supply side of the air conditioning unit, the water inlet side of the chilled water coil 7, and the return air side of the air conditioning unit, so as to detect the air supply temperature of the air conditioning unit, the water inlet temperature of the chilled water coil 7, and the return air temperature of the air conditioning unit. Of course, pressure sensors can also be arranged on the water inlet and outlet sides of the chilled water coil 7 according to actual conditions to detect the water inlet and outlet pressure difference of the chilled water coil 7.

[0048] The air-conditioning unit of the present application has an automatic switching function. The chilled water system is used as the main cooling method. After the automatic switching function is turned on, the chilled water system can be turned on first to make the air-conditioning unit operate in the chilled water mode to provide sufficient cooling capacity according to the actual cooling demand of the computer room.

[0049] During the operation of the air-conditioning unit in chilled water mode, since the chilled water system can adjust the cooling capacity it generates according to the actual cooling demand of the computer room, the supply air temperature of the unit can be kept less than or equal to the preset value when the chilled water system operates normally to meet the cooling demand of the computer room; if the supply air temperature of the unit is greater than the preset value at a certain moment or during a certain period of time, it means that the chilled water system may have a fault. Among them, when the circulating water flow of the chilled water coil 7 is insufficient, the circulating water inlet temperature is high, the control valve 10 fails, etc., the supply air temperature of the unit will be greater than the preset value.

[0050] When the chilled water system fails, the air supply temperature of the unit can no longer meet the cooling demand of the computer room. At this time, the fluorine system can be automatically turned on to make the air-conditioning unit run in fluorine mode and provide cooling through the backup fluorine system, thereby avoiding the temperature increase in the computer room.

[0051] When the air-conditioning unit is running in fluorine mode, the air-conditioning unit can also detect whether the chilled water has returned to normal. If not, it will continue to run in the fluorine system mode; if it has returned to normal, it will switch back to the chilled water system, thereby realizing automatic switching between the fluorine system and the chilled water system.

[0052] In addition, the air conditioning unit of the present application also has a manual switching function. When the chilled water system is ready for regular maintenance, it is manually switched to the fluorine system mode. When the chilled water system maintenance is completed, the system is manually switched back to the chilled water mode.

[0053] It can be seen that the chilled water system of the present application can judge the operating status in real time through the air outlet temperature of the air-conditioning unit, and quickly make corresponding switches according to different states, so that the air-conditioning unit can control the temperature of the computer room well and avoid temperature rise during the switching process.

[0054] In summary of the above embodiments, the air-conditioning unit of the present application can select an automatic switching mode, with the chilled water system as the main refrigeration mode. When the chilled water system fails, the air-conditioning unit can automatically switch to the standby fluorine system refrigeration mode to meet the cooling demand of the machine room and prevent the temperature in the machine room from rising. At the same time, the air-conditioning unit can identify whether the chilled water system has returned to normal. When the chilled water system has returned to normal, the air-conditioning unit can automatically switch to the chilled water system, which can also avoid the temperature rise in the machine room. The air-conditioning unit avoids the tedious manual switching and the increase in the temperature of the machine room caused by the untimely system switching. The air-conditioning unit of the present application can also select a manual mode. For a chilled water system that requires regular maintenance, the fluorine system refrigeration mode can be manually selected, and the chilled water mode can be switched back after the maintenance is completed. It is convenient and quick, and has a wider range of applications.

[0055] The number of fluorine systems in the present application is two groups, and the evaporators 2 in the two groups of fluorine systems are arranged front and back according to the return air direction, so that the return air from the machine room passes through the two evaporators 2 in sequence and is supplied to the machine room through the indoor fan.

[0056] The two fluorine systems can provide sufficient cooling capacity for the computer room when the chilled water coil 7 fails or is under maintenance. At the same time, the two fluorine systems can operate separately or simultaneously. When the chilled water coil 7 fails but can still provide a certain amount of cooling capacity, only one set of fluorine systems can be turned on to cooperate with the chilled water system, thereby saving power resources in the data center while meeting the cooling capacity requirements of the computer room.

[0057] The evaporator 2 of the fluorine system can be an evaporating coil, and the chilled water coil 7 corresponds to the position of the evaporating coil, so that the return air from the machine room passes through the chilled water coil 7 and the evaporating coil in sequence and then supplies air to the machine room, and at least one of the chilled water coil 7 and the evaporating coil can exchange heat with the return air from the machine room to reduce the heat of the return air from the machine room. Of course, the evaporating coil can also adopt a cross-type evaporating coil, that is, two groups of fluorine systems correspond to one evaporating coil, and the evaporating coil has two independent channels corresponding to the fluorine circulation loops 5 of the two groups of fluorine systems, and the two independent channels are cross-arranged, which will not be described in detail here, and all fall within the protection scope of this application.

[0058] The present application also provides a control method, which can be applied to the above-mentioned dual-cold-source air-conditioning unit. Please refer to FIG. 2 . The control method includes:

[0059] After the air conditioning unit is started, you can choose to run in automatic switching mode or manual switching mode according to the actual situation; when the chilled water system needs maintenance, you can choose the manual switching mode, and choose to run the fluorine system refrigeration in the manual switching mode, and choose the automatic switching mode in other cases. Of course, in the manual switching mode, if the chilled water system conditions are normal, you can also choose to run the chilled water system; the normal chilled water system conditions include no alarm on the inlet water temperature of the chilled water coil 7 (the inlet water temperature of the chilled water coil 7 must be lower than the supply air temperature of the machine room), and the inlet and outlet water pressure difference (temperature difference) of the chilled water coil 7 is greater than the set value;

[0060] Since the chilled water system is the main refrigeration system, the air conditioner unit will automatically operate in the chilled water mode after the automatic switching mode is selected; when the air conditioner unit operates in the chilled water mode, the air conditioner unit will automatically detect whether the chilled water system is faulty in real time. If there is a fault, the air conditioner unit will automatically switch to the fluorine mode; if there is no fault, it will continue to operate in the chilled water mode; based on the above, the air conditioner unit can quickly make corresponding judgments according to the operating status of the chilled water system (fault status and non-fault status), thereby ensuring the stability of the temperature in the computer room;

[0061] After the air-conditioning unit automatically switches to the fluorine mode, the air-conditioning unit can automatically detect whether the fault of the chilled water system is eliminated. If so, the air-conditioning unit automatically switches to the chilled water mode; if not, it continues to run the fluorine mode; so that after the chilled water system returns to normal, it can automatically switch to the chilled water mode to ensure that the chilled water system is the main refrigeration system.

[0062] Wherein, when the air conditioner unit is running in the chilled water mode, the step of the air conditioner unit automatically detecting whether the chilled water system is faulty comprises:

[0063] Determine whether the actual supply air temperature of the air-conditioning unit is higher than the preset supply air temperature. If not, it means that the chilled water system can meet the cooling demand of the computer room. At this time, the chilled water system has no faults and can operate continuously. If so, it means that the chilled water system cannot meet the cooling demand of the computer room. At this time, it is necessary to detect whether the control valve 10 is faulty or at the maximum opening. Specifically, if a fault in the control valve 10 is detected and continues for a preset time, it means that there is a fault in the chilled water system. Alternatively, if the chilled water system still cannot meet the cooling demand of the computer room when the control valve 10 is at the maximum opening, it means that the circulating water flow in the chilled water system is insufficient or the circulating water inlet temperature is too high, which also indicates that there is a fault in the chilled water system.

[0064] In general, when the air-conditioning unit is running in chilled water mode, as long as the actual air supply temperature of the air-conditioning unit is higher than the preset air supply temperature, it means that the chilled water system is faulty. As for the specific fault type, please refer to the above content.

[0065] The steps after the air conditioning unit automatically switches to the fluorine operation mode also include:

[0066] Determine whether the water inlet temperature of the chilled water coil 7 is higher than the return air temperature of the air conditioning unit. If so, it means that the chilled water coil 7 is no longer able to cool the return air of the machine room, so it is necessary to control the opening of the control valve 10 to the minimum opening; if not, it means that the chilled water coil 7 still has a cooling function, and the opening of the control valve 10 can be controlled to the maximum opening, thereby providing a certain amount of cooling for the return air of the machine room;

[0067] However, regardless of whether the control valve 10 is at the minimum or maximum opening, since the cooling capacity provided by the chilled water system can no longer meet the cooling demand of the computer room, the fluorine system can supplement sufficient cooling capacity for the computer room based on the current heat exchange capacity of the chilled water coil 7 and the cooling demand of the computer room. It should be pointed out that after a failure of the chilled water system, there will be a gradual recovery process, and the chilled water system can be restored to normal through staff inspection and other means. At this time, the heat exchange capacity of the chilled water coil 7 will gradually increase, so the operating frequency of the compressor 1 of the fluorine system also needs to be changed accordingly to adapt to the cooling demand of the computer room.

[0068] In addition, the steps for the air conditioning unit to automatically detect whether the fault of the chilled water system is eliminated include:

[0069] When compressor 1 is running at the lowest frequency, it is determined whether the actual air supply temperature of the air conditioning unit is less than or equal to the preset air supply temperature. If so, the fault of the chilled water system is eliminated after the fluorine system runs for a preset time; if not, the fault of the chilled water system is not eliminated;

[0070] It should be pointed out that when the chilled water system gradually returns to normal, the cooling capacity provided by the chilled water coil 7 gradually increases, and the fluorine system will correspondingly reduce the operating frequency of the compressor 1. When the compressor 1 reaches the minimum frequency, if the actual supply air temperature of the air-conditioning unit is less than or equal to the preset supply air temperature, it means that the cooling capacity provided by the chilled water system can meet the cooling capacity demand of the computer room, and after maintaining the preset time, the fault of the chilled water system is eliminated.

[0071] After the fluorine system has been running for a preset time, the steps after the chilled water system fault is eliminated include:

[0072] Close the fluorine system and detect the current opening of the control valve 10;

[0073] If the control valve 10 is at the maximum opening, it means that the room still needs the chilled water system to provide cooling capacity, and the air-conditioning unit operates in the chilled water mode;

[0074] If the control valve 10 is at the minimum opening, the chilled water system does not provide cooling at this time. At the same time, when the fluorine system is turned off, the actual supply air temperature of the air-conditioning unit is less than or equal to the preset supply air temperature, indicating that the computer room has no cooling demand. When both the chilled water system and the fluorine system are not running, the computer room still meets the cooling demand (when there is no cooling demand in the computer room, the fact that neither the chilled water system nor the fluorine system provides cooling can also be indicated as meeting the cooling demand of the computer room). At this time, the air-conditioning unit can enter the standby state to facilitate the next step of control.

[0075] It should be pointed out that when the air-conditioning unit is turned on, no matter what switching mode it is in and whether the chilled water system is running, the control valve 10 should at least maintain a minimum opening in a non-closed state to provide a more accurate inlet and outlet water temperature difference and pressure difference of the chilled water coil 7.

[0076] In addition, no matter whether the air conditioning unit directly operates the chilled water mode through the automatic switching mode, directly operates the chilled water mode through the manual switching mode, or switches to the chilled water mode through the fluorine system, when operating the chilled water mode, the fluorine system is in a closed state, that is, the compressor 1 and the fluorine pump 4 are not running, and the chilled water system can automatically adjust the opening of the control valve 10 according to the cooling demand of the machine room; wherein, when the chilled water system is fault-free, if it is adjusted according to the cooling demand of the machine room, the opening of the control valve 10 reaches the minimum opening, and continues for a preset time, it means that there is no cooling demand in the machine room, and the air conditioning unit can also enter the standby state. wherein, in the process of reducing the opening of the control valve 10, it should be gradually reduced by a certain small change, and the small change can be set according to the specific situation of the control valve 10.

[0077] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0078] Specific examples are used herein to illustrate the principles and implementation methods of the present application, and the description of the above embodiments is only used to help understand the method and core ideas of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A dual cold source air conditioning unit, characterized in that: Including chilled water system, fluorine system, temperature detection system; The chilled water system comprises a chilled water circulation loop (9) and a chilled water coil (7) arranged on the chilled water circulation loop (9); the chilled water circulation loop (9) is also provided with a control valve (10); The fluorine system comprises a compressor (1), a fluorine pump (4), an evaporator (2), a condenser (3) and a throttling element (6); the compressor (1), the fluorine pump (4), the evaporator (2), the condenser (3) and the throttling element (6) are connected to form a fluorine circulation loop (5) of the fluorine system; The temperature detection system comprises a plurality of temperature sensors, and the temperature detection system is used to detect the supply air temperature of the air conditioning unit, detect the water inlet temperature of the chilled water coil (7), and detect the return air temperature of the air conditioning unit.

2. The dual cold source air conditioning unit according to claim 1, characterized in that: The number of the fluorine systems is two groups, and the evaporators (2) in the two groups of the fluorine systems are arranged front and back according to the return air direction, so that the return air from the machine room passes through the two evaporators (2) in sequence and is supplied to the machine room through the indoor fan.

3. The dual cold source air conditioning unit according to claim 2, characterized in that: The evaporator (2) is an evaporation coil, and the chilled water coil (7) corresponds to the position of the evaporation coil, so that the return air from the machine room passes through the chilled water coil (7) and the evaporation coil in sequence and then is delivered into the machine room.

4. A control method, characterized in that: Applied to the dual cold source air conditioning unit according to any one of claims 1 to 3, the control method comprises: Determine whether an automatic switching mode signal is received when the air conditioning unit is running, and if so, control the air conditioning unit to automatically run in a chilled water mode; if not, control the air conditioning unit to run in a manual switching mode; When the air conditioning unit operates in the chilled water mode, the air conditioning unit automatically detects whether the chilled water system fails. If so, the air conditioning unit automatically switches to the fluorine mode; if not, the air conditioning unit continues to operate in the chilled water mode; After the air-conditioning unit automatically switches to the fluorine mode, the air-conditioning unit automatically detects whether the fault of the chilled water system is eliminated. If so, the air-conditioning unit automatically switches to the chilled water mode; if not, it continues to operate the fluorine mode.

5. The control method according to claim 4, characterized in that: When the air conditioning unit operates in the chilled water mode, the step of the air conditioning unit automatically detecting whether the chilled water system is faulty comprises: Determine whether the actual air supply temperature of the air conditioning unit is higher than the preset air supply temperature. If not, the chilled water system is not faulty. If so, detect whether the control valve (10) is faulty or is at the maximum opening. If the control valve (10) is faulty or the control valve (10) is at the maximum opening and remains at the maximum opening for a preset time, determine that the chilled water system is faulty.

6. The control method according to claim 5, characterized in that: After the air conditioning unit automatically switches to the fluorine mode, the method further includes: Determining whether the water inlet temperature of the chilled water coil (7) is higher than the return air temperature of the air conditioning unit, and if so, controlling the opening of the control valve (10) to be the minimum opening; if not, controlling the opening of the control valve (10) to be the maximum opening; The operating frequency of the compressor (1) of the fluorine system is adjusted according to the current heat exchange capacity of the chilled water coil (7) and the refrigeration demand of the machine room.

7. The control method according to claim 6, characterized in that: The air conditioning unit automatically detects whether the fault of the chilled water system is eliminated, including: When the compressor (1) is controlled to operate at the lowest frequency, it is determined whether the actual air supply temperature of the air conditioning unit is less than or equal to a preset air supply temperature. If so, the fault of the chilled water system is eliminated after the fluorine system operates for a preset time; if not, the fault of the chilled water system is not eliminated.

8. The control method according to claim 7, characterized in that: After the fluorine system runs for a preset time and the fault of the chilled water system is eliminated, the method further comprises: Controlling closing of the fluorine system and detecting the current opening of the control valve (10); If the control valve (10) is at the maximum opening, the chilled water mode is operated; If the control valve (10) is at the minimum opening, the machine room has no cooling demand and the air conditioning unit enters a standby state.

9. The control method according to any one of claims 5 to 8, characterized in that: When the air conditioning unit is in operation, the control valve (10) is controlled to at least maintain a minimum opening degree in a non-closed state.

10. The control method according to claim 9, characterized in that: When the air conditioning unit operates in the chilled water mode, the opening of the control valve (10) is adjusted according to the cooling demand of the machine room. After the opening of the control valve (10) reaches the minimum opening and continues for a preset time, the machine room has no cooling demand and the air conditioning unit enters a standby state.

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