A control method and device for an air conditioning system

Abstract

The present application discloses a control method and device for an air-conditioning system, and the air-conditioning system includes a chilled water system for storing cold energy. The method includes: determining that the air-conditioning system enters a chilled water storage mode according to the acquired air-conditioning operation data; determining an upper limit value and a lower limit value of the chilled water supply temperature according to the energy consumption information of the air-conditioning system operating in the chilled water storage mode; and controlling the chilled water storage mode according to the determined upper limit value and lower limit value of the chilled water supply temperature.

Description

Technical Field

[0001] The present application relates to the technical field of air conditioners, and particularly to a control method and device for an air conditioning system. Background Art

[0002] Air conditioning systems play a crucial role in improving the indoor environment of buildings and ensuring the comfort of indoor occupants. In large public buildings, the energy consumption of air conditioning systems accounts for more than 50% of the total building energy consumption, making them the main energy-consuming part of buildings. Therefore, the energy-saving optimization of heating, ventilation, and air conditioning (HVAC) systems is of great significance for the overall energy efficiency of buildings. Additionally, buildings still have a cooling demand during the spring and autumn seasons and at night in summer, when the cooling load is relatively small. To provide the corresponding cooling capacity, the chilled water units of central air conditioners operate at a relatively low energy efficiency. Sometimes, the minimum cooling capacity that the chilled water units can provide is still greater than the demand of the air conditioning system. At this time, since the air conditioning system cannot maintain the cooling capacity balance, the supply temperature of chilled water continuously decreases. When it drops to the shutdown protection point of the chilled water unit, the main unit shuts down. When the water temperature rises to the state where startup is allowed, the main unit starts again. This results in frequent start-stop of the main unit. At the same time, when the main unit is shut down, the cooling water pump and the cooling tower fan are still running, leading to waste of energy. Summary of the Invention

[0003] Embodiments of the present application provide a control method and device for an air conditioning system. By presetting the allowable range of the chilled water outlet temperature of the air conditioning main unit, the equipment of the air conditioning system is controlled to enter the chilled water storage mode, achieving energy savings in the system and reducing the start-stop times of the air conditioning main unit.

[0004] The solution provided by the embodiments of the present application is as follows: A control method for an air conditioning system, the air conditioning system includes a chilled water system for storing cooling capacity, and chilled water is stored in the chilled water system; the method includes:

[0005] Determining that the air conditioning system enters the chilled water storage mode according to the obtained air conditioning operation data;

[0006] Determining the upper limit value and the lower limit value of the chilled water supply temperature according to the energy consumption information of the air conditioning system operating in the chilled water storage mode;

[0007] Controlling the chilled water storage mode according to the determined upper limit value and lower limit value of the chilled water supply temperature.

[0008] In an exemplary embodiment, the air conditioning operation data includes: the chilled water supply temperature.

[0009] In an exemplary embodiment, the determining that the air conditioning system enters the chilled water storage mode according to the obtained air conditioning operation data includes:

[0010] Determine that the maximum temperature drop of the chilled water supply temperature is greater than or equal to a preset temperature drop, and the air-conditioning system enters the water-cooling storage mode for operation.

[0011] In an exemplary embodiment, after determining that the maximum temperature drop of the chilled water supply temperature is less than the preset temperature drop, before the air-conditioning system enters the chilled water storage mode for operation, it further includes:

[0012] Determine that the energy efficiency of the air-conditioning system is less than a predetermined percentage of the maximum energy efficiency.

[0013] In an exemplary embodiment, the maximum energy efficiency is determined by the following method:

[0014] According to the obtained chilled water supply temperature during the preset period of air-conditioning operation, perform fitting according to the fitting formula to determine the maximum energy efficiency;

[0015] Among them, the fitting formula is:

[0016]

[0017] In the above formula, CPP max is the maximum energy efficiency, and P 0 , P 1 , P 2 , P 3 , P 4 , P 5 are fitting parameters.

[0018] In an exemplary embodiment, the method for setting the upper and lower limits of the chilled water supply temperature corresponding to the first operating condition by using the pre-set upper and lower limits of the chilled water supply temperature setting optimization method includes:

[0019] Set the range of the upper limit value and the lower limit value of the chilled water supply temperature and the terminal cooling load information;

[0020] Monitor the current chilled water supply temperature;

[0021] Determine the minimum energy consumption according to the chilled water supply temperature, the flow rate of the chilled water main pipe, and the terminal cooling load information;

[0022] Determine the upper limit value and the lower limit value of the chilled water supply temperature according to the determined minimum energy consumption.

[0023] In an exemplary embodiment, the water-cooling storage mode includes a shutdown cooling mode and a startup refrigeration mode.

[0024] In an exemplary embodiment, the air-conditioning system further includes an air-conditioning main unit, a chiller, a cooling tower, and a cooling water pump;

[0025] Controlling the water-cooling energy storage mode according to the determined upper and lower limit values of the chilled water supply temperature includes:

[0026] Determine that the current number of operating air-conditioning main units is 1, and the operating air-conditioning main unit is the one with the smallest cooling capacity and no faults in the air-conditioning system, and the outlet water temperature of the chiller is less than the determined lower limit value of the chilled water supply temperature;

[0027] Determine that the startup time of the air-conditioning main unit is greater than the preset time period, then enter the shutdown cooling mode; wherein, entering the shutdown cooling mode includes: shutting down the chiller, shutting down the cooling tower, and shutting down the cooling water pump.

[0028] In an exemplary embodiment, controlling the water-cooling energy storage mode according to the determined upper and lower limit values of the chilled water supply temperature includes:

[0029] Determine that the outlet water temperature of the chiller is greater than the determined upper limit value of the chilled water supply temperature;

[0030] Determine that the startup time of the air-conditioning main unit is greater than the preset time period, then enter the startup cooling mode; wherein, entering the startup cooling mode includes: starting the cooling tower, starting the cooling water pump, and starting the chiller.

[0031] The embodiment of the present application also provides a control device for an air-conditioning system, the device includes: a memory and a processor; the memory is used to save the program for controlling the air-conditioning system, and the processor is used to read and execute the program for controlling the air-conditioning system, and execute the method described in any one of the above embodiments

[0032] The embodiment of the present application discloses a control method and device for an air-conditioning system, the air-conditioning system includes a chilled water system for storing cooling capacity, the method includes: determining that the air-conditioning system enters the water-cooling energy storage mode according to the obtained air-conditioning operation data; determining the upper and lower limit values of the chilled water supply temperature according to the energy consumption information of the air-conditioning system operating in the water-cooling energy storage mode; controlling the water-cooling energy storage mode according to the determined upper and lower limit values of the chilled water supply temperature. The present application controls the water-cooling energy storage mode by optimizing the upper and lower limit values of the water-cooling energy storage mode, so as to save system energy consumption and reduce the start-stop times of the air-conditioning main unit.

[0033] After reading and understanding the drawings and the detailed description, other aspects can be understood. Description of the Drawings

[0034] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0035] Figure 1 It is a flowchart of a control method for an air conditioning system in Embodiment 1 of the present application;

[0036] Figure 2 It is a schematic diagram of the operating states of system devices in different modes in an example;

[0037] Figure 3 It is a schematic diagram of the control logic for determining entry into the chilled water storage mode in an example;

[0038] Figure 4 It is a flowchart for optimizing the upper and lower limits of the chilled water temperature in an example;

[0039] Figure 5 It is a schematic diagram of the control logic for entering the chilled water storage mode in an example;

[0040] Figure 6 It is a schematic diagram of the control logic for exiting the chilled water storage mode in an example;

[0041] Figure 7 It is a schematic diagram of the control device of the air conditioning system in Embodiment 6 of the present application. Detailed implementation manners

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0043] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0044] In addition, in this application, descriptions such as "first" and "second" are only used to distinguish things or actions with the same name, and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of this application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0045] In this application, unless otherwise clearly specified and defined, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this invention can be understood according to specific circumstances.

[0046] In addition, the technical solutions between various embodiments of this application can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by this application.

[0047] Embodiment 1

[0048] This embodiment provides a control method for an air-conditioning system. As Figure 1 shown, the control method for this air-conditioning system includes steps S110 - S130, specifically as follows:

[0049] S110. Determine that the air-conditioning system enters the chilled water storage mode according to the obtained operation data of the air-conditioning system;

[0050] S120. Determine the upper limit value and the lower limit value of the chilled water supply temperature according to the energy consumption information of the air-conditioning system operating in the chilled water storage mode;

[0051] S130. Control the air-conditioning system to enter and exit the chilled water storage mode according to the determined upper limit value of the chilled water supply temperature and the lower limit value of the chilled water supply temperature.

[0052] In this embodiment, the changes in the operating states of each module in the air-conditioning system during the normal operation mode of the air-conditioning system are as Figure 2As shown in the figure; in the normal operation mode, when the cooling load demand of the air-conditioning system is low, the chiller of the air-conditioning system will operate at a low load rate. After the air-conditioning main unit operates for a short time, the supply water temperature of the chilled water reaches the temperature value at which the air-conditioning main unit enters the pause state, and the air-conditioning main unit will stop and enter the pause state. After a period of cooling, when the chilled water temperature rises to the set temperature for exiting the pause, the air-conditioning main unit will execute restart and refrigeration. In the normal operation mode of the air-conditioning system, when the main unit pauses, the chilled water pumps, cooling water pumps and cooling towers of the air-conditioning system all remain in operation. Therefore, in this operation mode, when the cooling load at the end of the air-conditioning system is small, the pause time of the air-conditioning main unit will be longer. When the air-conditioning main unit pauses, the power consumption of the cooling end equipment in the air-conditioning system is useless power consumption, which will increase the overall energy consumption of the air-conditioning system in vain.

[0053] The operating state changes of each module in the air-conditioning system when the air-conditioning system operates in the chilled water storage operation mode are as Figure 2 shown. In the chilled water storage operation mode, the air-conditioning system will shut down the air-conditioning main unit, the cooling water pump and the cooling tower, and only keep the chilled water pump running. Relying on the chilled water pump, the low-temperature chilled water prepared before the air-conditioning main unit stops is circulated to the end to supply cooling. The control process of the chilled water storage mode is as follows: when the air-conditioning main unit is operating at a low load rate and the return water temperature of the system chilled water is continuously decreasing, and the maximum temperature drop of the chilled water supply temperature is greater than or equal to the preset temperature drop, the chilled water storage mode is entered. After determining that the air-conditioning system enters the chilled water storage mode, the air-conditioning main unit, the cooling water pump, the cooling tower and the corresponding valves are closed, and only the chilled water pump is kept running. Relying on the chilled water pump, the low-temperature chilled water prepared before the air-conditioning main unit stops is transported to the end for cooling. In the air-conditioning system, the energy consumption of the air-conditioning system can be calculated by the following formula:

[0054] P sys =P ch +P chwp +P cwp +P ct

[0055] In the formula, P sys is the energy consumption of the machine room, P ch is the energy consumption of the air-conditioning main unit, P chwp is the energy consumption of the chilled water pump, P cwp is the energy consumption of the cooling water pump, P ct is the energy consumption of the cooling tower.

[0056] Compared with the normal operation mode of the air-conditioning system, when the air-conditioning system operates in the chilled water storage mode, the shutdown duration of the air-conditioning main unit can be extended. When the air-conditioning main unit shuts down, the cooling water pump and the cooling tower are shut down, reducing the energy consumption P cwp of the cooling water pump and the energy consumption P ct of the cooling tower, thereby reducing the total energy consumption P sys of the machine room and achieving the effect of energy saving.

[0057] In an exemplary embodiment, the air conditioner operation data includes: the chilled water supply temperature. Periodically detect the chilled water supply temperature in the air conditioning system. If it is determined that the maximum temperature drop of the chilled water supply temperature within the current period is greater than or equal to a preset temperature drop, the air conditioning system enters the chilled water storage mode of operation. The preset temperature drop can be determined according to manual experience. For example, the temperature drop is 3°C or 4°C.

[0058] In an exemplary embodiment, after periodically detecting the chilled water supply temperature in the air conditioning system and determining that the maximum temperature drop of the chilled water supply temperature within the current period is less than the preset temperature drop, further determine whether the energy efficiency of the air conditioning system is less than a predetermined percentage of the maximum energy efficiency. If the energy efficiency of the air conditioning system is less than the predetermined percentage of the maximum energy efficiency, the air conditioning system enters the chilled water storage mode of operation. In this embodiment, the maximum energy efficiency can be determined by the following method:

[0059] Obtain the chilled water supply temperature of the air conditioner operation within a preset time period, and fit the chilled water supply temperatures corresponding to multiple monitoring time points according to the fitting formula to determine the maximum energy efficiency;

[0060] Among them, the fitting formula is:

[0061] P 1 、P 2 、P 3 、P 4 、P 5 are fitting parameters.

[0062] In an exemplary embodiment, determining the upper limit value and the lower limit value of the chilled water supply temperature according to the energy consumption information of the air conditioning system operating in the chilled water storage mode includes:

[0063] First step, preset the allowable range of the upper limit value and the lower limit value of the chilled water supply temperature according to experience;

[0064] Second step, determine the current terminal cooling load, and determine whether the current operating condition is the first operating condition according to the cooling load; among them, the first operating condition refers to the operating condition where the power consumption is lower than the preset lower limit value of the power consumption;

[0065] Third step, monitor the chilled water supply temperature within the monitoring period;

[0066] Fourth step, determine the minimum energy consumption according to the monitoring data of the chilled water supply temperature, the flow rate, the flow rate of the chilled water main pipe, and the data information of the terminal cooling load;

[0067] Fifth step, determine the upper limit value and the lower limit value of the chilled water supply temperature according to the determined minimum energy consumption.

[0068] In an exemplary embodiment, the water-cooling storage mode includes a shutdown cooling mode and a startup refrigeration mode.

[0069] The air-conditioning system further includes an air-conditioning main unit, a chiller, a cooling tower, and a cooling water pump.

[0070] Controlling the water-cooling storage mode according to the determined upper and lower limit values of the chilled water supply temperature includes: determining that the current number of operating air-conditioning main units is 1, and the operating air-conditioning main unit is the one with the smallest cooling capacity and no faults in the air-conditioning system, and the outlet water temperature of the chiller is less than the determined lower limit value of the chilled water supply temperature; determining that the startup time of the air-conditioning main unit is greater than a preset time period, then entering the shutdown cooling mode; wherein, entering the shutdown cooling mode includes: turning off the chiller, turning off the cooling tower, and turning off the cooling water pump. Controlling the water-cooling storage mode according to the determined upper and lower limit values of the chilled water supply temperature includes: determining that the outlet water temperature of the chiller is greater than the determined upper limit value of the chilled water supply temperature; determining that the startup time of the air-conditioning main unit is greater than a preset time period, then entering the startup refrigeration mode; wherein, entering the startup refrigeration mode includes: turning on the cooling tower, turning on the cooling water pump, and turning on the chiller.

[0071] In the embodiment of the present application, during the operation of the water-cooling storage mode of the central air-conditioning system, there is no relatively clear control method, and no operation strategy with the lowest energy efficiency can be given. In this embodiment, for this situation, for a refrigeration system that allows the chilled water supply temperature to fluctuate within a certain range, the water-cooling storage operation mode of the chiller under low load rate is improved, and the on-off temperature of the chiller with the lowest energy consumption is obtained through an optimization algorithm, so that the chiller operates intermittently under high load rate, providing an energy-efficient operation strategy.

[0072] Embodiment 2

[0073] Taking the application scenario of sudden drop in cooling load under night conditions as an example, the flowchart for judging whether to enter the water-cooling storage mode is as Figure 3 shown, and the process for judging whether to enter the water-cooling storage mode is as follows:

[0074] Step 1. The air-conditioning system enters the night condition, and the cooling load drops suddenly. In this scenario, it is judged that this night condition is the first condition, that is, the low load rate operation condition;

[0075] Step 2. Monitor the air-conditioning operation data for a period of time; for example: the monitored data of the chilled water supply temperature of the air-conditioning system within 30 minutes;

[0076] Step 3. Determine whether the maximum temperature drop of the chilled water supply temperature within 30 minutes is less than the pre-set temperature T °C; wherein, this temperature T °C can be set to 3 °C or 4 °C according to human experience;

[0077] Step 4. During this monitoring period, if the temperature drop of the chilled water supply is greater than or equal to T °C, it is determined that the current air-conditioning system cannot maintain the stability of the chilled water supply temperature, that is, it is judged that the cooling load of the air-conditioning system is less than the minimum refrigeration capacity of the air-conditioning host, and the energy efficiency of the air-conditioning system is low. Control the air-conditioning system to enter the water storage cooling mode for operation;

[0078] Step 5. During this monitoring period, if the temperature drop of the chilled water supply is less than T °C, it is determined that the current air-conditioning system can maintain the stability of the chilled water supply temperature, that is, it is judged that the cooling load of the air-conditioning system is greater than or equal to the minimum refrigeration capacity of the host; the air-conditioning system continues to execute Step 6;

[0079] Step 6. Calculate the maximum COP according to the chilled water return temperature and the maximum COP calculation model under the night condition; among them, it is determined that the maximum COP can be calculated by the following formula:

[0080]

[0081] Step 7. Under the current night condition, judge whether the current COP of the air-conditioning system is less than a predetermined ratio of the maximum COP, for example: 90%;

[0082] Step 8. If it is determined that the COP of the air-conditioning system is greater than or equal to 90% of the maximum COP, it is considered that the air-conditioning system operates efficiently under this night condition and does not enter the water storage cooling mode;

[0083] Step 9. If it is determined that the COP of the air-conditioning system is less than 90% of the maximum COP, it is considered that the air-conditioning system has low operating efficiency under the night condition and is allowed to enter the water storage cooling mode.

[0084] Embodiment 3

[0085] The flow chart for optimizing the upper and lower limits of the chilled water temperature corresponding to the entry and exit of the water storage cooling mode of the air-conditioning system is as Figure 4 shown:

[0086] Step 1. Set the allowable range of the upper and lower limits of the chilled water supply temperature and the terminal cooling load

[0087] Step 2. Establish a temperature rise time model and a temperature drop time model for the chilled water supply temperature

[0088] Step 3. Calculate the change of the chilled water supply temperature during the entire night condition according to the model

[0089] Step 4. Input the chilled water supply temperature change, flow rate, and terminal cooling load data into the energy consumption calculation model;

[0090] Step 5. Calculate the minimum energy consumption condition according to the particle swarm optimization algorithm;

[0091] Step 6. Output the set values of the upper and lower limits of the chilled water supply temperature corresponding to the minimum energy consumption condition.

[0092] Example 4

[0093] Taking the application scenario of sudden drop in cooling load under night conditions as an example, the process of the air-conditioning system entering the chilled water storage mode is as Figure 5 shown below:

[0094] Step 1. Determine whether the number of operating air-conditioning main units is 1;

[0095] Step 2. Determine whether the currently operating air-conditioning main unit is the one with the smallest cooling capacity and no faults;

[0096] Step 3. Determine that the maximum temperature drop of the chilled water supply temperature is less than the preset temperature drop;

[0097] Step 4. When the conditions of the above three steps are met and the startup time of the air-conditioning main unit is greater than or equal to the preset duration, for example: the preset duration n_1 can be 60 minutes, then the air-conditioning system enters the chilled water storage mode;

[0098] Step 5. Shut down the chiller of the air-conditioning system;

[0099] Step 6. Shut down the cooling tower of the air-conditioning system and shut down the cooling water pump of the air-conditioning system.

[0100] Example 5

[0101] Taking the application scenario of sudden drop in cooling load under night conditions as an example, the process of the air-conditioning system exiting the chilled water storage mode is as Figure 6 shown below:

[0102] Step 1. Determine that the air-conditioning system is in the chilled water storage mode;

[0103] Step 2. Judge whether the chilled water outlet temperature of the chiller is ≥ T2; when it is determined that the chilled water outlet temperature of the chiller is greater than the upper limit value of the preset chilled water supply temperature, execute Step 3;

[0104] Step 3. Judge whether the shutdown time of the air-conditioning main unit reaches n2 minutes; when it is determined that the shutdown time of the air-conditioning main unit reaches n2 minutes, execute Step 4; where, the shutdown time n2 of the air-conditioning main unit can be set according to the actual situation, for example: 20 minutes;

[0105] Step 4. If the conditions of the above three steps are met, the air-conditioning system exits the chilled water storage mode;

[0106] Step 5. Turn on the cooling tower of the air-conditioning system and turn on the cooling water pump of the air-conditioning system;

[0107] Step 6. Turn on the chiller with no faults and the smallest cooling capacity to complete the control of exiting the chilled water storage mode.

[0108] Example 6

[0109] To achieve the above object, an embodiment of the present application provides a control device for an air-conditioning system, the device comprising: a memory 710 and a processor 720; the memory is used to store a program for controlling the air-conditioning system, and the processor is used to read and execute the program for controlling the air-conditioning system, and execute the method described in any one of the above embodiments.

[0110] The beneficial effects of the present application are as follows: A method for optimizing the operation control of an air-conditioning system under low-load conditions is proposed, which can automatically control the start and stop of the air-conditioning system equipment according to the change of the chilled water return temperature of the air-conditioning system, achieving the effect of prolonging the shutdown duration of the main unit and reducing the start-stop times of the main unit. At the same time, it can also reduce the loss of the service life of the equipment caused by the frequent start and stop of the main unit. When the main unit is shut down, the control method can automatically turn off the system cooling pump and cooling tower, reduce the system power consumption, improve the energy efficiency of the air-conditioning system, and achieve a more energy-saving effect.

[0111] Those of ordinary skill in the art can understand that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, and their appropriate combinations. In the hardware implementation, the division of the functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be executed by several physical components in cooperation. Some or all of the components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include a computer storage medium (or non-transitory medium) and a communication medium (or transitory medium). As is well known to those of ordinary skill in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cassette, tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, as is well known to those of ordinary skill in the art, a communication medium typically includes computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and can include any information delivery medium.

Claims

1. A control method for an air conditioning system, characterized in that, the air conditioning system includes a chilled water system for storing cooling capacity, an air conditioning main unit, a chiller, a cooling tower and a cooling water pump, and chilled water is stored in the chilled water system; the method includes: determining that the air conditioning system enters the chilled water storage mode according to the obtained air conditioning operation data, including: determining that the maximum temperature drop of the chilled water supply temperature is greater than or equal to a preset temperature drop, and controlling the air conditioning system to enter the chilled water storage mode; determining the upper limit value and the lower limit value of the chilled water supply temperature according to the energy consumption information of the air conditioning system operating in the chilled water storage mode, including: setting the range of the upper limit value and the range of the lower limit value of the chilled water supply temperature and the terminal cooling load information; monitoring the current chilled water supply temperature; determining the minimum energy consumption according to the chilled water supply temperature, the flow rate of the chilled water main pipe and the terminal cooling load information; determining the upper limit value and the lower limit value of the chilled water supply temperature according to the determined minimum energy consumption; controlling the chilled water storage mode according to the determined upper limit value and the lower limit value of the chilled water supply temperature; the controlling the chilled water storage mode according to the determined upper limit value and the lower limit value of the chilled water supply temperature includes: determining that the current number of operating air conditioning main units is 1, and the operating air conditioning main unit is the main unit with the smallest cooling capacity and no fault in the air conditioning system, and the outlet water temperature of the chiller is less than the determined lower limit value of the chilled water supply temperature; determining that the startup time of the air conditioning main unit is greater than a preset time period, then entering the shutdown cooling mode; wherein, the entering the shutdown cooling mode includes: shutting down the chiller, shutting down the cooling tower and shutting down the cooling water pump; determining that the outlet water temperature of the chiller is greater than the determined upper limit value of the chilled water supply temperature; determining that the startup time of the air conditioning main unit is greater than a preset time period, then entering the startup refrigeration mode; wherein, the entering the startup refrigeration mode includes: starting the cooling tower, starting the cooling water pump and starting the chiller.

2. The control method for an air conditioning system according to claim 1, characterized in that, after determining that the maximum temperature drop of the chilled water supply temperature is greater than or equal to a preset temperature drop, before the air conditioning system enters the chilled water storage mode operation, it further includes: determining that the energy efficiency of the air conditioning system is less than a predetermined percentage of the highest energy efficiency; the highest energy efficiency is determined by the following method: obtaining the chilled water supply temperature of the air conditioning operation within a preset time period, and fitting according to a fitting formula to determine the highest energy efficiency; wherein, the fitting formula is: In the above formula, COP max is the highest energy efficiency, and P 0 , P 1 , P 2 , P 3 , P 4 , P 5 are fitting parameters.

3. A control device for an air conditioning system, the control device includes: a memory and a processor; characterized in that the memory is used to store a program for controlling the air conditioning system, and the processor is used to read and execute the program for controlling the air conditioning system, and execute the control method according to any one of claims 1-2.

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