Control method, control apparatus, water chilling unit, and computer readable storage medium

Abstract

The present disclosure provides a control method, a control apparatus, a water chilling unit, and a computer readable storage medium. The control method comprises: when a plurality of modules of a water chilling unit are all running or only some of the modules are running, if among all running modules there exists at least one module having a load greater than a first threshold value and there exists at least one module having a load smaller than a second threshold value, then obtaining, among all the running modules, a module having the highest load and a module having the lowest load, the first threshold value being greater than the second threshold value; calculating a first difference value between the highest load and a third threshold value and a second difference value between the third threshold value and the lowest load; and when at least one of the first difference value and the second difference value is greater than a fourth threshold value and a difference value between the highest load and the lowest load is greater than a fifth threshold value, executing a load shedding operation on the module having the highest load and executing a load addition operation on the module having the lowest load.

Description

Control method, control device, chiller and computer-readable storage medium

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the application with CN application number 202311112187.X and application date August 30, 2023, and claims its priority. The disclosed content of the CN application is hereby introduced as a whole into this application. Technical Field

[0003] The present disclosure relates to the technical field of chillers, and in particular to a control method, a control device, a chiller, and a computer-readable storage medium. Background Art

[0004] Under the same operating conditions, the load control of the chiller between 70% and 80% will achieve the optimal energy efficiency ratio. However, in the load control strategy of the multi-module chiller in the related technology, the operating load control of multiple modules is usually kept consistent, that is, some modules remain fully loaded while some modules are on standby, or multiple modules maintain a low-frequency operating state for a long time.

[0005] Summary of the Invention

[0006] According to one aspect of the present disclosure, a control method for a chiller is provided, wherein the chiller includes multiple modules, and the control method includes: when all the multiple modules of the chiller are in operation or only some of the modules are in operation, if there is at least one module whose load is greater than a first threshold and there is at least one module whose load is less than a second threshold among all the operating modules, then obtaining the module with the highest load and the module with the lowest load among all the operating modules, wherein the first threshold is greater than the second threshold; calculating a first difference between the highest load and a third threshold and a second difference between the third threshold and the lowest load; and when at least one of the first difference and the second difference is greater than a fourth threshold and the difference between the highest load and the lowest load is greater than a fifth threshold, performing a load reduction operation on the module with the highest load and performing a load operation on the module with the lowest load.

[0007] In some embodiments, performing a load reduction operation on the module with the highest load and performing a load operation on the module with the lowest load includes: detecting the rate of change of the outlet water temperature of the chiller; and when the rate of change of the outlet water temperature is less than a sixth threshold, performing a load reduction operation on the module with the highest load and performing a load operation on the module with the lowest load.

[0008] In some embodiments, a load shedding operation is performed on the module with the highest load to reduce the load of the module with the highest load to the third threshold; and a load loading operation is performed on the module with the lowest load to increase the reduced load of the module with the highest load.

[0009] In some embodiments, the control method further includes: performing a first control operation on all running modules when the loads of all running modules are less than the second threshold.

[0010] In some embodiments, performing a first control operation on all running modules includes: when all running modules are one module, keeping the current running state of the module unchanged; when all running modules are two modules, if the sum of the loads of the two modules is less than or equal to the seventh threshold, shutting down the module with the longer running time among the two modules, and performing a loading operation on the other module among the two modules, otherwise keeping the current running state of the two modules unchanged; and when the number of all running modules is greater than 2, shutting down the module with the longest running time among all running modules, and performing a loading operation on the remaining running modules.

[0011] In some embodiments, performing a first control operation on all running modules includes: when all running modules are one module, keeping the current running state of the module unchanged; when the number of all running modules is greater than or equal to 2, detecting the running time of all running modules; when there is at least one module among all running modules whose running time is less than or equal to an eighth threshold, keeping the current running state of all running modules unchanged; and when the running time of all running modules is greater than the eighth threshold, performing corresponding processing on the running modules according to the number of all running modules.

[0012] In some embodiments, corresponding processing of the running modules according to the number of all running modules includes: when there are two modules in all running modules, if the sum of the loads of the two modules is less than or equal to the seventh threshold, shutting down the module with the longer running time among the two modules, and performing a loading operation on the other module of the two modules, otherwise keeping the current running status of the two modules unchanged; and when the number of all running modules is greater than 2, shutting down the module with the longest running time among all running modules, and performing a loading operation on the remaining running modules.

[0013] In some embodiments, the control method further includes: when only some of the multiple modules of the chiller are operating, if the loads of all the operating modules are greater than the first threshold, performing a second control operation on all the operating modules.

[0014] In some embodiments, performing the second control operation on all running modules includes: performing a load reduction operation on all running modules and starting one module.

[0015] In some embodiments, performing a second control operation on all running modules includes: detecting the rate of change of the outlet water temperature of the chiller; when the rate of change of the outlet water temperature is greater than or equal to a ninth threshold value, maintaining the current operating state of all running modules for a predetermined period of time, and re-detecting the rate of change of the outlet water temperature of the chiller after the predetermined period of time; and when the rate of change of the outlet water temperature is less than the ninth threshold value, performing a load reduction operation on all running modules and turning on one module.

[0016] In some embodiments, a load shedding operation is performed on all running modules to reduce the loads of all running modules to the third threshold.

[0017] In some embodiments, the third threshold is an optimal load value for module operation.

[0018] In some embodiments, the third threshold is equal to the first threshold.

[0019] According to another aspect of the present disclosure, a control device for a chiller is provided, wherein the chiller includes multiple modules, and the control device includes: an acquisition unit for acquiring the module with the highest load and the module with the lowest load among all the running modules if, when all the multiple modules of the chiller are running or only some of the modules are running, there is at least one module whose load is greater than a first threshold and there is at least one module whose load is less than a second threshold among all the running modules, wherein the first threshold is greater than the second threshold; a calculation unit for calculating a first difference between the highest load and a third threshold and a second difference between the third threshold and the lowest load; and an execution control unit for performing a load reduction operation on the module with the highest load and a loading operation on the module with the lowest load when at least one of the first difference and the second difference is greater than a fourth threshold and the difference between the highest load and the lowest load is greater than a fifth threshold.

[0020] According to another aspect of the present disclosure, a control device for a chiller is provided, comprising: a memory; and a processor coupled to the memory, wherein the processor is configured to execute the aforementioned control method based on instructions stored in the memory.

[0021] According to another aspect of the present disclosure, a chiller is provided, comprising: the control device as described above.

[0022] In some embodiments, the chiller further comprises: a plurality of modules, each module comprising a compressor, a condenser and an evaporator.

[0023] According to another aspect of the present disclosure, a computer-readable storage medium is provided, on which computer program instructions are stored. When the computer program instructions are executed by a processor, the control method as described above is implemented.

[0024] According to another aspect of the present disclosure, a computer program is provided, comprising: instructions, which, when executed by a processor, enable the processor to perform the control method as described above.

[0025] Other features and advantages of the present disclosure will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0027] The present disclosure can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0028] FIG1 is a flow chart illustrating a control method for a chiller according to some embodiments of the present disclosure;

[0029] 2 is a flowchart illustrating a method for performing a first control operation on all running modules in a control method according to some embodiments of the present disclosure;

[0030] 3 is a flowchart illustrating a method for performing a first control operation on all running modules in a control method according to other embodiments of the present disclosure;

[0031] FIG4 is a block diagram schematically illustrating a structure of a control device for a chiller according to some embodiments of the present disclosure;

[0032] FIG5 is a block diagram schematically illustrating a structure of a control device for a chiller according to other embodiments of the present disclosure;

[0033] FIG6 is a block diagram schematically illustrating a structure of a control device for a chiller according to other embodiments of the present disclosure;

[0034] FIG7 is a block diagram schematically illustrating a structure of a chiller according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0035] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure.

[0036] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0037] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0038] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0039] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0040] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0041] In the load control strategy of the multi-module chiller in the related art, the operating load control of multiple modules is usually kept consistent, that is, some modules remain fully loaded while some modules are on standby, or multiple modules maintain a low-frequency operating state for a long time, which leads to relatively low operating energy efficiency of the multi-module chiller in the related art.

[0042] In view of this, an embodiment of the present disclosure provides a control method for a chiller to improve the operating energy efficiency of a multi-module chiller.

[0043] In the embodiments of the present disclosure, the chiller comprises multiple modules. Each module includes a compressor, a condenser, an evaporator, and the like. In other words, each module is a complete circulation system, including a compressor, a condenser, an evaporator, and the like. The entire system composed of multiple modules constitutes the chiller.

[0044] FIG1 is a flow chart illustrating a control method for a chiller according to some embodiments of the present disclosure. The chiller includes multiple modules. As shown in FIG1 , the control method includes steps S102 to S106.

[0045] In step S102, when multiple modules of the chiller are all running or only some of the modules are running, if there is at least one module whose load is greater than a first threshold value among all the running modules and there is at least one module whose load is less than a second threshold value, then the module with the highest load and the module with the lowest load among all the running modules are obtained, wherein the first threshold value is greater than the second threshold value.

[0046] In this step, the reason why the module with the highest load and the module with the lowest load among all the running modules are obtained when there is at least one module with a load greater than the first threshold and at least one module with a load less than the second threshold among all the running modules is that if there is at least one module with a load greater than the first threshold and at least one module with a load less than the second threshold among all the running modules, it means that the difference between the module with the highest load and the module with the lowest load is relatively large. In this case, it is easy for the loads of multiple modules of the chiller to be too uneven. Therefore, the module with the highest load and the module with the lowest load among all the running modules are obtained, and corresponding load balancing operations may be performed.

[0047] For example, when the unit is powered on, it detects whether all modules are running. Regardless of whether all modules are running or only some of them are running, the running load of each module in all running modules is detected, and it is determined whether there is at least one module whose load is greater than a first threshold and at least one module whose load is less than a second threshold among all running modules. If so, the module with the highest load and the module with the lowest load are obtained from all running modules.

[0048] In some embodiments, the first threshold ranges from 70% to 80%. For example, the first threshold is 75%. The range of the first threshold is derived from actual engineering data and test evaluations. According to simulation tests, within a fixed ambient temperature range, the unit achieves the highest energy efficiency and cost-effectiveness when operating in the 70% to 80% load range. Therefore, the above range of the first threshold facilitates screening of modules operating at loads above the optimal load.

[0049] Of course, those skilled in the art will appreciate that the above range of the first threshold is merely exemplary, and the scope of the present disclosure is not limited to a specific value of the first threshold. The first threshold can be set according to actual needs or circumstances.

[0050] In some embodiments, the second threshold value ranges from 50% to 65%. For example, the second threshold value is 65%. In measured data, under the same ambient temperature, when the load is operated below 65%, there is a significant drop in energy efficiency, and the cooling capacity is less cost-effective. In addition, because the load of most fixed-frequency units is limited to 50% (it should be noted that 25% is only for extreme loads), setting the second threshold value range between 50% and 65% can effectively determine whether the unit load meets the requirements, while avoiding the inability to enter this control logic due to the second threshold value being too low.

[0051] Of course, those skilled in the art will appreciate that the above range of the second threshold is merely exemplary, and the scope of the present disclosure is not limited to a specific value of the second threshold. The second threshold can be set according to actual needs or circumstances.

[0052] In step S104 , a first difference between the highest load and a third threshold value and a second difference between the third threshold value and the lowest load are calculated.

[0053] That is, the first difference A is A=Q H -Y3, (1)

[0054] Among them, Q H is the highest load (also called the maximum load), and Y3 is the third threshold.

[0055] The second difference B is B=Y3-Q L , (2)

[0056] Among them, Y3 is the third threshold, Q L It is the lowest load (also called minimum load).

[0057] In some embodiments, the third threshold is the optimal load value for module operation. This facilitates calculation of the difference between the highest load and the optimal load value, as well as the difference between the optimal load value and the lowest load, thereby facilitating the understanding of the deviation of the highest-loaded module and the lowest-loaded module from the optimal load value, and then performing corresponding processing based on the deviation.

[0058] In some embodiments, the third threshold is equal to the first threshold. The two thresholds are equal, which facilitates the implementation of the control method and is beneficial to the subsequent control of the load of the modules of the chiller.

[0059] In some embodiments, the range of the third threshold is 70% to 80%. For example, the third threshold is 75%. Similar to the first threshold, the range of the third threshold is derived from actual engineering data and test evaluation. According to simulation tests, within a fixed ambient temperature range, when the unit operates in a load segment of 70% to 80%, the unit's energy efficiency ratio and cost performance are the highest. Therefore, the above range of the third threshold facilitates the calculation of the difference between the highest load and the optimal load value, as well as the difference between the optimal load value and the lowest load, thereby facilitating the understanding of the deviation of the highest load module and the lowest load module from the optimal load value, and then performing corresponding processing according to the deviation.

[0060] Of course, those skilled in the art will appreciate that the above range of the third threshold is merely exemplary, and the scope of the present disclosure is not limited to a specific value of the third threshold. The third threshold can be set according to actual needs or circumstances.

[0061] In step S106 , when at least one of the first difference and the second difference is greater than a fourth threshold and the difference between the highest load and the lowest load is greater than a fifth threshold, a load reduction operation is performed on the module with the highest load and a load operation is performed on the module with the lowest load.

[0062] For example, determine whether the first difference and the second difference are both smaller than the fourth threshold value. If so, the operation of the module is now within the optimal operation section, so the module can be processed. For example, the process can return to the step of detecting whether all modules are running when the group is in the power-on state at the beginning of the program; otherwise, it indicates that at least one of the first difference and the second difference is greater than the fourth threshold value, then determine whether the difference between the highest load and the lowest load (i.e., QH-QL) is less than or equal to the fifth threshold value.

[0063] If the difference between the highest load and the lowest load is less than or equal to the fifth threshold, the module will not be processed. For example, the process can return to the step when the program starts and the group is in the powered-on state to detect whether all modules are running; otherwise, it indicates that the difference between the highest load and the lowest load is greater than the fifth threshold, then the unloading operation is performed on the module with the highest load, and the loading operation is performed on the module with the lowest load.

[0064] Here, the load reduction operation is an operation to reduce the operating load (also called unloading operation), that is, an operation to reduce the output capacity of the chiller; the loading operation is an operation to increase the operating load, that is, an operation to increase the output capacity of the chiller.

[0065] In some embodiments, the fourth threshold is in a range of 5% to 10%. For example, the fourth threshold is 5%. The fourth threshold is set to determine whether the first difference and the second difference are within a relatively small range, thereby facilitating subsequent operations when at least one of the first difference and the second difference is greater than the fourth threshold.

[0066] Of course, those skilled in the art will appreciate that the above range of the fourth threshold is merely exemplary, and the scope of this disclosure is not limited to a specific value of the fourth threshold. The fourth threshold can be set according to actual needs or circumstances.

[0067] In some embodiments, the fifth threshold value ranges from 12% to 18%. For example, the fifth threshold value is 15%. The range of the fifth threshold value is intended to determine the relationship between the difference between the highest load and the lowest load and the fifth threshold value. Therefore, when the difference between the highest load and the lowest load is greater than the fifth threshold value, it indicates that the difference between the highest load and the lowest load is relatively large. In this case, the loads of multiple modules of the chiller are likely to be too uneven. Therefore, a load reduction operation is performed on the module with the highest load, and a load is performed on the module with the lowest load, so that the load distribution of the modules can be as even as possible.

[0068] Of course, those skilled in the art will appreciate that the above range of the fifth threshold is merely exemplary, and the scope of the present disclosure is not limited to the specific value of the fifth threshold. The fifth threshold can be set according to actual needs or circumstances.

[0069] In some embodiments, a load shedding operation is performed on the module with the highest load to reduce the load of the module with the highest load to a third threshold. This facilitates the operation of the module with the highest load at its optimum load, thereby maximizing the uniformity of the load distribution across the modules (i.e., the load distribution after adjustment is more uniform than the original load distribution), thereby improving the energy efficiency of the multi-module chiller.

[0070] In some embodiments, if there are multiple modules with the highest load, the module with the longest running time is selected to enter the optimal load adjustment, that is, the load reduction operation is performed on the module with the highest load and the longest running time. When this adjustment is completed, the optimal load detection and judgment are re-performed and adjusted one by one, so as to avoid the impact on the user side as much as possible.

[0071] In some embodiments, a loading operation is performed on the module with the lowest load to increase the load reduced by the module with the highest load. In other words, the load of the module with the lowest load is increased by the same amount as the load of the module with the highest load is reduced. In other words, the load reduced by the module with the highest load is added to the module with the lowest load. In this way, the load distribution of the modules can be made as uniform as possible (i.e., the load distribution after adjustment is more uniform than the original load distribution) without changing the overall load of the chiller, thereby improving the operating energy efficiency of the multi-module chiller.

[0072] So far, a control method for a chiller according to some embodiments of the present disclosure is provided. The control method includes: when multiple modules of the chiller are all running or only some modules are running, if there is at least one module whose load is greater than a first threshold value and at least one module whose load is less than a second threshold value among all the running modules, then obtaining the module with the highest load and the module with the lowest load among all the running modules, wherein the first threshold value is greater than the second threshold value; calculating the first difference between the highest load and the third threshold value and the second difference between the third threshold value and the lowest load; and when at least one of the first difference and the second difference is greater than a fourth threshold value and the difference between the highest load and the lowest load is greater than a fifth threshold value, performing a load reduction operation on the module with the highest load and performing a load operation on the module with the lowest load. This method can make the load distribution of the modules tend to be uniform as much as possible, that is, the load distribution after adjustment is more uniform than the original load distribution, thereby improving the operating energy efficiency of the multi-module chiller.

[0073] In some embodiments, performing a load reduction operation on the module with the highest load and performing a load operation on the module with the lowest load includes: detecting the rate of change of the outlet water temperature of the chiller; and when the rate of change of the outlet water temperature is less than a sixth threshold, performing a load reduction operation on the module with the highest load and performing a load operation on the module with the lowest load.

[0074] For example, in typical engineering applications, the water systems of a single chiller are connected in series, and there may be only one outlet. Therefore, the outlet water temperature of the chiller can be obtained from this outlet, and the rate of change of the outlet water temperature can be calculated. For another example, if the chiller has multiple outlets, multiple outlet water temperatures can be obtained from these outlets, and the average of these temperatures can be calculated to calculate the rate of change of the outlet water temperature.

[0075] The calculation formula for the water temperature change rate ΔT is:

[0076] Among them, T0 is the initial outlet water temperature of the chiller, T t The outlet water temperature after time t, where t is the elapsed time. For example, t is 10 seconds.

[0077] In the above embodiment, before the load shedding and loading operations are performed on the modules, a water temperature change rate judgment condition is added. When all modules are turned on, if the water temperature change rate ΔT ≥ the sixth threshold value ΔTc, it proves that the actual demand on the user side is changing rapidly at this time, and the current operating status of the unit is maintained. For example, the process can return to the step of detecting whether all modules are running when the unit is in the on state at the beginning of the program; if the water temperature change rate ΔT < ΔTc, it indicates that the water temperature change rate is slow, indicating that the load fluctuation on the user side is not large, and each module is in a steady state, and each module can be optimally load regulated. Therefore, the above embodiment achieves the purpose of optimally load regulating the modules when the load fluctuation on the user side is not large and each module is in a steady state, facilitates the implementation of load regulation, and also reduces the possibility of load conditions being performed when the actual demand on the user side changes rapidly and causes failures.

[0078] In the above embodiment, the reason why the water temperature change rate ΔT ≥ ΔTc proves that the actual demand on the user side changes rapidly at this time, and the current operation status of the unit is maintained without any processing. This is because the actual demand on the user side changes rapidly, indicating that the actual demand on the user side is changing (for example, the morning working hours of an office building). At this time, there are module opening and closing actions. Entering the optimal load regulation may disrupt the control of the unit startup and affect the demand on the user side. Therefore, the adjustment of the optimal load can be made when the operation of the unit is basically stable.

[0079] In some embodiments, a load reduction operation is performed on the module with the highest load to reduce the load of the module with the highest load to a third threshold, and a load increase operation is performed on the module with the lowest load to increase the load reduced by the module with the highest load. This can achieve a more even load distribution among the modules (i.e., the load distribution after adjustment is more even than the original load distribution) without changing the overall load of the chiller, thereby improving the operating energy efficiency of the multi-module chiller.

[0080] In some embodiments, the sixth threshold ranges from 0.5°C / min (degrees Celsius / minute) to 1°C / min. Generally, a water temperature change rate below 0.5°C / min indicates normal operating fluctuations, while a water temperature change rate exceeding 1°C / min may make the determination range too stringent, making it difficult to achieve optimal load regulation. Therefore, the sixth threshold range facilitates optimal load regulation of the module.

[0081] Of course, those skilled in the art will appreciate that the above range of the sixth threshold is merely exemplary, and the scope of this disclosure is not limited to the specific value of the sixth threshold. The sixth threshold can be set according to actual needs or circumstances.

[0082] In other embodiments, as described above, instead of detecting the rate of change of the chiller's outlet water temperature in step 106, the load shedding operation may be performed directly on the module with the highest load, and the loading operation may be performed on the module with the lowest load. This can simplify the procedure and facilitate implementation.

[0083] In some embodiments, the control method further includes: performing a first control operation on all running modules when the loads of all running modules are less than a second threshold.

[0084] For example, when all the multiple modules of the chiller are running (i.e., all modules are running), in the process of determining whether there is at least one module among all the running modules whose load is greater than the first threshold and at least one module whose load is less than the second threshold, if yes, obtain the module with the highest load and the module with the lowest load from all the running modules; if not, determine whether the loads of all the running modules are less than the second threshold; if the loads of all the running modules are less than the second threshold, perform the first control operation on all the running modules; otherwise, do not process the module, for example, the process can return to the step of detecting whether all modules are running when the unit is in the power-on state at the beginning of the program.

[0085] In the above embodiment, when the loads of all operating modules are less than the second threshold, the first control operation is performed on all operating modules, thereby entering the multi-module low-load operation control mode. This facilitates improving the operating energy efficiency of the multi-module chiller when the loads of all operating modules are low.

[0086] In some embodiments, when only some modules are operating, the system can first detect whether the load of all operating modules is less than a second threshold, and then determine whether at least one module among all operating modules has a load greater than the first threshold and at least one module has a load less than the second threshold. In other words, if some modules are in standby mode and not turned on, it indicates that the actual required load is relatively low. In this case, it is more likely that multiple modules will operate at low loads. From the perspective of communication control and reliability, multiple separate control paths and fewer judgment conditions can make the system more stable and reduce the occurrence of communication failures.

[0087] In some embodiments, performing the first control operation on all running modules includes: when all running modules are one module, keeping the current running state of the module unchanged; when all running modules are two modules, if the sum of the loads of the two modules is less than or equal to a seventh threshold, shutting down the module with the longer running time of the two modules and performing a loading operation on the other module of the two modules, otherwise keeping the current running state of the two modules unchanged; and when the number of all running modules is greater than 2, shutting down the module with the longest running time of all running modules and performing a loading operation on the remaining running modules. In this embodiment, in the process of executing the first control operation, by executing different control logics for different numbers of running modules, corresponding processing can be performed for different numbers of running modules, thereby improving the operating energy efficiency of the multi-module chiller.

[0088] For example, in the process of executing the first control operation on all running modules, if the number of all running modules is 1, since only one module is running, there is no need to process the module, and the current running state of the module remains unchanged.

[0089] For another example, when performing the first control operation on all running modules, if the number of all running modules is 2, it is determined whether the sum of the loads of the two modules is less than or equal to the seventh threshold. If so, it indicates that turning on one module can meet the demand, so the module with the longer running time can be turned off, and a loading operation can be performed on the other module of the two modules, for example, the load of the turned-off module can be added to the running module; if the sum of the loads of the two modules is greater than the seventh threshold, it indicates that turning on one module cannot meet the demand, so the current operating status of the two modules needs to be kept unchanged. Such control logic can maximize the operating energy efficiency of the multi-module chiller.

[0090] In some embodiments, the seventh threshold value ranges from 70% to 80%. For example, the seventh threshold value is 80%. The seventh threshold value range can enable the multi-module chiller to operate at optimal energy efficiency.

[0091] Of course, those skilled in the art will appreciate that the above range of the seventh threshold is merely exemplary, and the scope of the present disclosure is not limited to the specific value of the seventh threshold. The seventh threshold can be set according to actual needs or circumstances.

[0092] In addition, it should be noted that when the sum of the loads of the above-mentioned two modules is less than or equal to the seventh threshold, if the running time of the two modules is equal, any one of the two modules can be closed and a loading operation can be performed on the other module. That is to say, the running time of one of the modules can be artificially regarded as a longer running time, thereby shutting down the module and performing a loading operation on the other module.

[0093] For another example, during the process of executing the first control operation on all running modules, if the number of all running modules is greater than 2, the module with the longest running time among all running modules is shut down, and a loading operation is performed on the remaining running modules. For example, during the process of performing the loading operation on the remaining running modules, the load of the shut down module can be detected and the load can be evenly loaded onto the remaining modules. After loading is completed, if the low-load multi-module operation is still met, this operation is repeated. In this embodiment, by shutting down the module with the longest running time among all running modules and performing the loading operation on the remaining running modules, the operating energy efficiency of the multi-module chiller can be improved.

[0094] In other embodiments, performing the first control operation on all running modules includes: when all running modules are one module, keeping the current running state of the module unchanged; when the number of all running modules is greater than or equal to 2, detecting the running time of all running modules; when there is at least one module whose running time is less than or equal to an eighth threshold value among all running modules, keeping the current running state of all running modules unchanged; and when the running time of all running modules is greater than the eighth threshold value, performing corresponding processing on the running modules according to the number of all running modules. In this embodiment, in the process of performing the first control operation, different control logics are executed on different numbers of running modules, so that corresponding processing can be performed for different numbers of running modules. Moreover, when the number of all running modules is greater than or equal to 2, the running modules are also combined with the running time of all running modules and processed accordingly according to the number of all running modules, which can improve the operating energy efficiency of the multi-module chiller.

[0095] For example, in the process of executing the first control operation on all running modules, if the number of all running modules is 1, since only one module is running, there is no need to process the module, and the current running state of the module remains unchanged.

[0096] For another example, if the number of all running modules is greater than or equal to 2, the running time of all running modules is detected; if the running time of at least one module among all running modules is less than or equal to the eighth threshold, it indicates that the at least one module may have been turned on for a short time, and therefore, the current running state of all running modules is maintained unchanged. This can minimize the risk of failure caused by subsequent processing (such as shutdown) after the module is turned on; if the running time of all running modules is greater than the eighth threshold, the running modules are processed accordingly based on the number of all running modules.

[0097] In some embodiments, the eighth threshold value ranges from 10 minutes to 20 minutes. This time range of the eighth threshold value can avoid the situation where the module is turned off immediately after being turned on.

[0098] Of course, those skilled in the art will appreciate that the above range of the eighth threshold is merely exemplary, and the scope of the present disclosure is not limited to the specific value of the eighth threshold. The eighth threshold can be set according to actual needs or circumstances.

[0099] In some embodiments, corresponding processing of the running modules according to the number of all running modules includes: when there are two modules in all running modules, if the sum of the loads of the two modules is less than or equal to the seventh threshold, shutting down the module with the longer running time among the two modules, and performing a loading operation on the other module of the two modules, otherwise keeping the current running status of the two modules unchanged; and when the number of all running modules is greater than 2, shutting down the module with the longest running time among all running modules, and performing a loading operation on the remaining running modules.

[0100] That is, in the above embodiment, if the operating time of all running modules is greater than the eighth threshold and the number of all running modules is 2, then it is determined whether the sum of the loads of the two modules is less than or equal to the seventh threshold. If so, it indicates that turning on one module can meet the demand, so the module with the longer operating time of the two modules can be turned off, and a loading operation can be performed on the other module of the two modules, for example, the load of the turned-off module can be added to the running module; if the sum of the loads of the two modules is greater than the seventh threshold, it indicates that turning on one module cannot meet the demand, so the current operating status of the two modules needs to be kept unchanged. Such control logic can maximize the operating energy efficiency of the multi-module chiller.

[0101] Furthermore, if the operating time of all running modules is greater than the eighth threshold and the number of all running modules is greater than 2, the module with the longest operating time among all running modules is shut down, and a loading operation is performed on the remaining running modules. For example, during the process of performing the loading operation on the remaining running modules, the load of the shut down modules can be detected and the load can be evenly loaded onto the remaining modules. After the loading is completed, if the low-load multi-module operation is still met, this operation is repeated. In this embodiment, by shutting down the module with the longest operating time among all running modules and performing the loading operation on the remaining running modules, the operating energy efficiency of the multi-module chiller can be improved.

[0102] In some embodiments, the control method also includes: when all the multiple modules of the chiller are running, if the loads of all the running modules (i.e., the multiple modules) are greater than or equal to a first threshold, it means that the demand is large at this time and there is no need to perform optimal load control. For example, the process can return to the step of detecting whether all modules are running when the unit is in the on state at the beginning of the program.

[0103] In some embodiments, the control method further includes: when only some of the multiple modules of the chiller are operating, if the load of all the operating modules is greater than a first threshold, performing a second control operation on all the operating modules. In this embodiment, when only some of the modules are operating, if the load of the modules is greater than the first threshold, performing the second control operation on all the operating modules, thereby improving the operating energy efficiency of the multi-module chiller.

[0104] In some embodiments, performing the second control operation on all running modules includes performing a load reduction operation on all running modules and turning on one module. In this embodiment, performing the load reduction operation on all running modules can reduce the excessive load on these modules, and turning on the one module normally can make up for the reduced load, thereby improving the operating energy efficiency of the multi-module chiller.

[0105] For example, a load shedding operation is performed on all running modules to reduce the load of all running modules to a third threshold value, so that all running modules tend to be closer to the optimal load as much as possible, thereby improving the operating energy efficiency of the multi-module chiller.

[0106] In other embodiments, performing a second control operation on all running modules includes: detecting the rate of change of the outlet water temperature of the chiller; when the rate of change of the outlet water temperature is greater than or equal to a ninth threshold value, maintaining the current operating state (i.e., the current operating mode) of all running modules for a predetermined period of time, and re-detecting the rate of change of the outlet water temperature of the chiller after the predetermined period of time; and when the rate of change of the outlet water temperature is less than the ninth threshold value, performing a load reduction operation on all running modules and turning on one module.

[0107] In the above embodiment, when only some modules are operating, if the rate of change ΔT of the outlet water temperature is greater than or equal to the ninth threshold ΔTd, turning on the remaining modules will likely cause greater water temperature fluctuations, triggering the unit to enter standby mode, so the above delay processing is performed. If the rate of change ΔT of the outlet water temperature is less than the ninth threshold ΔTd, indicating that the water temperature change rate fluctuates slightly, optimal load adjustment is performed, that is, load reduction is performed on all operating modules, and one module is turned on. This can improve the operating energy efficiency of the multi-module chiller.

[0108] For example, a load shedding operation is performed on all running modules to reduce the load of all running modules to a third threshold value, so that all running modules tend to be closer to the optimal load as much as possible, thereby improving the operating energy efficiency of the multi-module chiller.

[0109] In some embodiments, the ninth threshold ranges from 1.0°C / min to 1.5°C / min. Within this water temperature change rate determination range, it is possible to determine whether there is a sudden change in user demand (e.g., during the evening rush hour in an office building) or a sudden decrease in demand. For example, during the shutdown process of the module, no adjustment may be performed to minimize malfunctions.

[0110] Of course, those skilled in the art will appreciate that the above range of the ninth threshold is merely exemplary, and the scope of the present disclosure is not limited to the specific value of the ninth threshold. The ninth threshold can be set according to actual needs or circumstances.

[0111] In some embodiments, the predetermined time range is 3 minutes to 5 minutes. Such a time range is convenient for responding to changes in water temperature.

[0112] Of course, those skilled in the art will appreciate that the above range of the predetermined duration is merely exemplary, and the scope of the present disclosure is not limited to a specific value of the predetermined duration. The predetermined duration can be set according to actual needs or circumstances.

[0113] FIG2 is a flow chart illustrating a method for performing a first control operation on all running modules in a control method according to some embodiments of the present disclosure. When the loads of all running modules are less than a second threshold, the first control operation is performed on all running modules. As shown in FIG2 , the method includes steps S202 to S216.

[0114] In step S202, the number n of running modules is detected. Here, n is a positive integer. When n ≥ 2, the process proceeds to step S204; when n = 1, the process proceeds to step S206.

[0115] In step S204, the running time of all running modules is detected.

[0116] In step S206, the current running state is maintained.

[0117] In step S208, it is determined whether the running time of all running modules is greater than the eighth threshold. If so, the process proceeds to step S206. If not, and n=2, the process proceeds to step S210. If not, and n>2, the process proceeds to step S212.

[0118] In step S210, it is determined whether the sum of the loads of the two modules is less than or equal to the seventh threshold. If so, the process proceeds to step S214; otherwise, the process proceeds to step S216.

[0119] In step S212, the module with the longest running time among all running modules is closed, and a loading operation is performed on the remaining running modules.

[0120] In step S214, the module with the longer running time among the two modules is closed, and a loading operation is performed on the other module among the two modules.

[0121] In step S216, the current running state is maintained.

[0122] So far, a method for performing a first control operation on all running modules in a control method according to some embodiments of the present disclosure is provided. In this method, in the process of performing the first control operation, different control logics are executed on different numbers of running modules, so that corresponding processing can be performed for different numbers of running modules. Moreover, when the number of all running modules is greater than or equal to 2, the running modules are processed accordingly according to the number of all running modules in combination with the running time of all running modules, which can improve the operating energy efficiency of the multi-module chiller. The above-mentioned first control operation can also try to prevent multiple modules from running at low load or low frequency for a long time.

[0123] FIG3 is a flow chart illustrating a method for performing a first control operation on all running modules in a control method according to other embodiments of the present disclosure. When the load of all running modules is less than a second threshold, the first control operation is performed on all running modules. As shown in FIG3 , the method includes steps S302 to S312.

[0124] In step S302, the number n of running modules is detected. Here, n is a positive integer. When n=2, the process proceeds to step S304; when n=1, the process proceeds to step S310; when n>2, the process proceeds to step S312.

[0125] In step S304, it is determined whether the sum of the loads of the two modules is less than or equal to the seventh threshold. If so, the process proceeds to step S306; otherwise, the process proceeds to step S308.

[0126] In step S306, the module with the longer running time among the two modules is closed, and a loading operation is performed on the other module among the two modules.

[0127] In step S308, the current running state is maintained.

[0128] In step S310, the current running state is maintained.

[0129] In step S312, the module with the longest running time among all running modules is closed, and a loading operation is performed on the remaining running modules.

[0130] Thus, a method for performing a first control operation on all operating modules in a control method according to other embodiments of the present disclosure has been provided. In this method, during the execution of the first control operation, different control logic is applied to different numbers of operating modules, thereby enabling corresponding processing to be performed for different numbers of operating modules, thereby improving the operating energy efficiency of a multi-module chiller. This first control operation can also minimize the prolonged operation of multiple modules at low load or low frequency.

[0131] The method of the embodiment of the present disclosure detects the operating load of each module in the power-on state, coordinates module scheduling with the loading or unloading of a single module, so that the entire chiller can reach the optimal operating state in a more efficient and energy-saving operation mode.

[0132] FIG4 is a block diagram schematically illustrating a control device for a chiller according to some embodiments of the present disclosure. The chiller includes multiple modules. As shown in FIG4 , the control device includes: an acquisition unit 402 , a calculation unit 404 , and an execution control unit 406 .

[0133] The acquisition unit 402 is used to obtain the module with the highest load and the module with the lowest load among all the running modules when all modules of the chiller are running or only some of the modules are running, if the load of at least one module among all the running modules is greater than a first threshold and the load of at least one module is less than a second threshold, wherein the first threshold is greater than the second threshold.

[0134] The calculation unit 404 is configured to calculate a first difference between the highest load and a third threshold value and a second difference between the third threshold value and the lowest load.

[0135] The execution control unit 406 is configured to perform a load reduction operation on the module with the highest load and a load operation on the module with the lowest load when at least one of the first difference and the second difference is greater than a fourth threshold and the difference between the highest load and the lowest load is greater than a fifth threshold.

[0136] Thus, a control device for a chiller according to some embodiments of the present disclosure is provided. The control device includes: an acquisition unit for acquiring the module with the highest load and the module with the lowest load among all the running modules if, when all or only some of the modules of the chiller are running, the load of at least one module among all the running modules is greater than a first threshold and the load of at least one module is less than a second threshold, wherein the first threshold is greater than the second threshold; a calculation unit for calculating a first difference between the highest load and a third threshold and a second difference between the third threshold and the lowest load; and an execution control unit for performing a load reduction operation on the module with the highest load and a load loading operation on the module with the lowest load when at least one of the first difference and the second difference is greater than a fourth threshold and the difference between the highest load and the lowest load is greater than a fifth threshold. The control device can make the load distribution of the modules tend to be uniform as much as possible, that is, the load distribution after adjustment is more uniform than the original load distribution, thereby improving the operating energy efficiency of the multi-module chiller.

[0137] In some embodiments, the execution control unit 406 is used to detect the rate of change of the outlet water temperature of the chiller, and when the rate of change of the outlet water temperature is less than a sixth threshold, perform a load reduction operation on the module with the highest load and perform a load operation on the module with the lowest load.

[0138] In some embodiments, the execution control unit 406 is configured to perform a load reduction operation on the highest-loaded module to reduce the load of the highest-loaded module to a third threshold, and perform a load reduction operation on the lowest-loaded module to increase the reduced load of the highest-loaded module.

[0139] In some embodiments, the execution control unit 406 is further configured to execute the first control operation on all running modules when the loads of all running modules are less than a second threshold.

[0140] In some embodiments, the execution control unit 406 is used to: when all running modules are one module, keep the current running state of the module unchanged; when all running modules are two modules, if the sum of the loads of the two modules is less than or equal to the seventh threshold, shut down the module with the longer running time among the two modules, and perform a loading operation on the other module among the two modules, otherwise keep the current running state of the two modules unchanged; and when the number of all running modules is greater than 2, shut down the module with the longest running time among all running modules, and perform a loading operation on the remaining running modules.

[0141] In some embodiments, the execution control unit 406 is used to: when all running modules are one module, keep the current running state of the module unchanged; when the number of all running modules is greater than or equal to 2, detect the running time of all running modules; when there is at least one module among all running modules whose running time is less than or equal to the eighth threshold, keep the current running state of all running modules unchanged; and when the running time of all running modules is greater than the eighth threshold, perform corresponding processing on the running modules according to the number of all running modules.

[0142] In some embodiments, the execution control unit 406 is used to: when there are two modules in total, if the sum of the loads of the two modules is less than or equal to the seventh threshold, shut down the module with the longer running time among the two modules, and perform a loading operation on the other module of the two modules, otherwise keep the current running status of the two modules unchanged; and when the number of all running modules is greater than 2, shut down the module with the longest running time among all running modules, and perform a loading operation on the remaining running modules.

[0143] In some embodiments, the execution control unit 406 is further configured to execute a second control operation on all running modules when only some of the multiple modules of the chiller are running and the loads of all running modules are greater than a first threshold.

[0144] In some embodiments, the execution control unit 406 is configured to perform a load shedding operation on all running modules and start a module.

[0145] In some embodiments, the execution control unit 406 is used to detect the rate of change of the outlet water temperature of the chiller. When the rate of change of the outlet water temperature is greater than or equal to a ninth threshold value, the current operating state of all running modules is maintained for a predetermined period of time, and the rate of change of the outlet water temperature of the chiller is re-detected after the predetermined period of time. When the rate of change of the outlet water temperature is less than the ninth threshold value, a load reduction operation is performed on all running modules, and one module is turned on.

[0146] In some embodiments, the execution control unit 406 is configured to perform a load reduction operation on all running modules to reduce the loads of all running modules to a third threshold.

[0147] In some embodiments, the third threshold is an optimal load value for module operation.

[0148] In some embodiments, the third threshold is equal to the first threshold.

[0149] FIG5 is a block diagram schematically illustrating a control device for a chiller according to other embodiments of the present disclosure. The control device includes a memory 510 and a processor 520.

[0150] The memory 510 may be a disk, a flash memory, or any other non-volatile storage medium. The memory is used to store instructions in at least one of the embodiments corresponding to FIG. 1 to FIG. 3 .

[0151] Processor 520 is coupled to memory 510 and can be implemented as one or more integrated circuits, such as a microprocessor or microcontroller. Processor 520 is configured to execute instructions stored in memory to maximize load uniformity across the modules. Specifically, the adjusted load distribution is more uniform than the original load distribution, thereby improving the energy efficiency of the multi-module chiller.

[0152] In some embodiments, as shown in FIG6 , the control device 600 may include a memory 610 and a processor 620. The processor 620 is coupled to the memory 610 via a BUS 630. The control device 600 may also be connected to an external storage device 650 via a storage interface 640 to access external data, and may also be connected to a network or another computer system (not shown) via a network interface 660, which will not be described in detail here.

[0153] In this embodiment, by storing data instructions in a memory and then processing the above instructions through a processor, the load distribution of the modules can be made as uniform as possible. That is, compared with the original load distribution, the adjusted load distribution is more uniform, thereby improving the operating energy efficiency of the multi-module chiller.

[0154] According to some embodiments of the present disclosure, a chiller is further provided, which includes the control device as described above (such as the control device shown in Figure 4, Figure 5 or Figure 6).

[0155] FIG7 is a block diagram schematically illustrating a structure of a chiller according to some embodiments of the present disclosure.

[0156] As shown in Figure 7 , the chiller includes a control device 710. For example, the control device 710 is the control device shown in Figure 4 , Figure 5 , or Figure 6 .

[0157] In some embodiments, as shown in FIG7 , the chiller further comprises a plurality of modules 1 to m, where m is a positive integer. Each module comprises a compressor, a condenser, and an evaporator.

[0158] In other embodiments, the present disclosure further provides a computer-readable storage medium (e.g., a non-transitory computer-readable storage medium) having computer program instructions stored thereon, which, when executed by a processor, implement the steps of the method in at least one of the corresponding embodiments in Figures 1 to 3. Those skilled in the art will appreciate that the embodiments of the present disclosure may be provided as methods, devices, or computer program products. Therefore, the present disclosure may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present disclosure may take the form of a computer program product implemented on one or more computer-usable non-transitory storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0159] In some embodiments of the present disclosure, a computer program is further provided, comprising: instructions, which, when executed by a processor, enable the processor to perform the control method as described above.

[0160] The present disclosure is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present disclosure. It should be understood that each process and / or box in the flowchart and / or block diagram and the combination of the processes and / or boxes in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate a device for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0161] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0162] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0163] The present disclosure has been described in detail so far. To avoid obscuring the concept of the present disclosure, some details known in the art have not been described. Based on the above description, those skilled in the art can fully understand how to implement the technical solutions disclosed herein.

[0164] Although some specific embodiments of the present disclosure have been described in detail by way of examples, those skilled in the art will appreciate that the above examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Those skilled in the art will appreciate that modifications may be made to the above embodiments without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A control method for a chiller, wherein: The chiller includes multiple modules, and the control method includes: In the case that all the multiple modules of the chiller are in operation or only some of the modules are in operation, if the load of at least one module among all the operating modules is greater than a first threshold and the load of at least one module is less than a second threshold, then obtaining the module with the highest load and the module with the lowest load among all the operating modules, wherein the first threshold is greater than the second threshold; calculating a first difference between the highest load and a third threshold value and a second difference between the third threshold value and the lowest load; and When at least one of the first difference and the second difference is greater than a fourth threshold and the difference between the highest load and the lowest load is greater than a fifth threshold, a load reduction operation is performed on the module with the highest load and a load operation is performed on the module with the lowest load.

2. The control method according to claim 1, wherein: Performing a load reduction operation on the module with the highest load and performing a load operation on the module with the lowest load includes: Detecting the rate of change of the outlet water temperature of the chiller; and When the rate of change of the outlet water temperature is less than a sixth threshold, a load reduction operation is performed on the module with the highest load, and a load loading operation is performed on the module with the lowest load.

3. The control method according to claim 1 or 2, wherein: performing a load shedding operation on the module with the highest load to reduce the load of the module with the highest load to the third threshold; A loading operation is performed on the lowest-loaded module to increase the load reduced by the highest-loaded module.

4. The control method according to any one of claims 1 to 3, further comprising: When the loads of all the running modules are less than the second threshold, the first control operation is performed on all the running modules.

5. The control method according to claim 4, wherein: Executing the first control operation on all running modules includes: When all running modules are one module, the current running state of the module is kept unchanged; In the case that there are two modules among all the modules in operation, if the sum of the loads of the two modules is less than or equal to the seventh threshold, shutting down the module with the longer operation time among the two modules, and performing a loading operation on the other module among the two modules, otherwise keeping the current operation states of the two modules unchanged; and When the number of all running modules is greater than 2, the module with the longest running time among all running modules is closed, and a loading operation is performed on the remaining running modules.

6. The control method according to claim 4, wherein: Executing the first control operation on all running modules includes: When all running modules are one module, the current running state of the module is kept unchanged; When the number of all running modules is greater than or equal to 2, the running time of all running modules is detected; In the case that the running time of at least one module among all the running modules is less than or equal to the eighth threshold, keeping the current running states of all the running modules unchanged; and When the running time of all running modules is greater than the eighth threshold, the running modules are processed accordingly according to the number of all running modules.

7. The control method according to claim 6, wherein: The running modules are processed accordingly according to the number of all running modules, including: In the case that there are two modules among all the modules in operation, if the sum of the loads of the two modules is less than or equal to the seventh threshold, shutting down the module with the longer operation time among the two modules, and performing a loading operation on the other module among the two modules, otherwise keeping the current operation states of the two modules unchanged; and When the number of all running modules is greater than 2, the module with the longest running time among all running modules is closed, and a loading operation is performed on the remaining running modules.

8. The control method according to any one of claims 1 to 7, further comprising: In the case that only some of the multiple modules of the chiller are in operation, if the loads of all the operating modules are greater than the first threshold, a second control operation is performed on all the operating modules.

9. The control method according to claim 8, wherein: Executing the second control operation on all running modules includes: Perform load shedding operations on all running modules and start one module.

10. The control method according to claim 8, wherein: Executing the second control operation on all running modules includes: Detecting the rate of change of the outlet water temperature of the chiller; When the rate of change of the outlet water temperature is greater than or equal to a ninth threshold value, maintaining the current operating state of all operating modules for a predetermined period of time, and re-detecting the rate of change of the outlet water temperature of the chiller after the predetermined period of time; and When the rate of change of the outlet water temperature is less than the ninth threshold, a load reduction operation is performed on all running modules, and one module is turned on.

11. The control method according to claim 9 or 10, wherein: A load shedding operation is performed on all the running modules to reduce the loads of all the running modules to the third threshold.

12. The control method according to any one of claims 1 to 11, wherein: The third threshold is an optimal load value for module operation.

13. The control method according to any one of claims 1 to 12, wherein: The third threshold is equal to the first threshold.

14. A control device for a chiller, wherein: The chiller comprises a plurality of modules, and the control device comprises: An acquisition unit, configured to acquire a module with the highest load and a module with the lowest load among all the running modules if, in a case where all the multiple modules of the chiller are running or only some of the modules are running, the load of at least one module among all the running modules is greater than a first threshold and the load of at least one module is less than a second threshold, wherein the first threshold is greater than the second threshold; A calculation unit, configured to calculate a first difference between the highest load and a third threshold and a first difference between the third threshold and the A second difference in the lowest load; and An execution control unit is configured to perform a load reduction operation on the module with the highest load and a load operation on the module with the lowest load when at least one of the first difference and the second difference is greater than a fourth threshold and the difference between the highest load and the lowest load is greater than a fifth threshold.

15. A control device for a chiller, comprising: Memory; as well as A processor coupled to the memory, wherein the processor is configured to execute the control method according to any one of claims 1 to 13 based on instructions stored in the memory.

16. A chiller comprising: A control device as claimed in claim 14 or 15.

17. The chiller according to claim 16, further comprising: Multiple modules, each module includes a compressor, a condenser and an evaporator.

18. A computer-readable storage medium having computer program instructions stored thereon, wherein the computer program instructions, when executed by a processor, implement the control method according to any one of claims 1 to 13.

19. A computer program comprising: Instructions, when executed by a processor, cause the processor to perform the control method according to any one of claims 1 to 13.

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