Controller of freezer, freezer system, control method for freezer and program

Abstract

To provide a controller of a freezer, a freezer, a freezer system, a control method for a freezer and a program, which can stabilize a cooling water outlet temperature upon controlling the number of multiple freezers, without requiring an additional configuration such as a bypass pipe or two-way valve.SOLUTION: A controller that controls first and second freezers connected in series, comprises an additional freezer processing control unit that, when increasing the operation from only the first freezer to both the first and second freezers in response to increase in a load, controls a freezing capacity of the first freezer so that it is equal to or less than the freezing capacity at the start of the additional freezer processing from the start of the additional freezer processing to the completion of the additional freezer processing.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a refrigerator control device, a refrigerator system, a refrigerator control method, and a program. [Background technology]

[0002] In a chiller system that cools a load, the chilled water lines of multiple chillers are connected in series, and by controlling the number of chillers in operation, it is possible to operate efficiently over a wide capacity range. However, if the number of chillers in operation changes due to the control of the number of chillers, the chilled water outlet temperature may become unstable. Therefore, technology has been proposed to stabilize the chilled water outlet temperature even when the number of chillers in operation is controlled.

[0003] For example, Patent Document 1 discloses a technology for stabilizing the chilled water outlet temperature by using a bypass pipe that connects the chilled water outlet pipe and the chilled water inlet pipe of a group of chillers in which the chilled water systems of multiple chillers are connected in series, and two-way valves that operate in reverse, and by controlling the set temperature of the chillers and the opening of the two-way valves. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-355938 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology disclosed in Patent Document 1 requires bypass piping and a two-way valve in addition to the refrigerator, which may complicate the equipment structure and increase installation costs.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a chiller control device, a chiller, a chiller system, a chiller control method, and a program that can stabilize the chilled water outlet temperature when controlling the number of chillers, without requiring additional configuration such as bypass piping and a two-way valve. [Means for solving the problem]

[0007] The refrigerator control device according to the present disclosure is a control device that controls a first refrigerator and a second refrigerator connected in series, and includes an additional refrigerator processing control unit that, when increasing the operation from the first refrigerator alone to the first refrigerator and the second refrigerator in response to an increase in load, controls the refrigeration capacity of the first refrigerator to be equal to or less than the refrigeration capacity at the start of the additional refrigerator processing from the start of the additional refrigerator processing to the completion of the additional refrigerator processing.

[0008] The chiller control method according to the present disclosure is a control method for controlling a first chiller and a second chiller connected in series, and when increasing the operation from the first chiller alone to the first chiller and the second chiller in response to an increase in load, includes a step of controlling the chiller capacity of the first chiller to be equal to or less than the chiller capacity at the start of the additional chiller process from the start of the additional chiller process to the completion of the additional chiller process.

[0009] The program according to the present disclosure causes a computer of a control device that controls a first refrigerator and a second refrigerator connected in series to execute a step of controlling the refrigeration capacity of the first refrigerator so that it is equal to or less than the refrigeration capacity at the start of the additional refrigerator processing from the start of the additional refrigerator processing to the completion of the additional refrigerator processing when the operation of the first refrigerator alone is increased to the operation of the first refrigerator and the second refrigerator in response to an increase in load. [Effects of the Invention]

[0010] According to the chiller control device, chiller system, chiller control method, and program disclosed herein, it is possible to stabilize the chilled water outlet temperature when controlling the number of chillers without requiring additional components such as bypass piping and two-way valves. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a refrigerator system according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is an explanatory diagram illustrating a first refrigerator and a second refrigerator connected in series, which are included in the refrigerator system according to the first embodiment of the present disclosure. [Figure 3] 1 is a diagram illustrating a functional configuration of a control device for a refrigerator according to a first embodiment of the present disclosure. [Figure 4] FIG. 3 is a first flowchart showing an example of processing in a control method for a refrigerator according to a first embodiment of the present disclosure. [Figure 5] FIG. 2 is a second flowchart showing an example of processing in the refrigerator control method according to the first embodiment of the present disclosure. [Figure 6] FIG. 10 is a third flowchart showing an example of processing in the refrigerator control method according to the first embodiment of the present disclosure. [Figure 7] FIG. 3 is a first explanatory diagram illustrating the relationship between the vane opening degree of the first refrigerator and the vane opening degree of the second refrigerator in the refrigerator control method according to the first embodiment of the present disclosure. [Figure 8] FIG. 10 is a second explanatory diagram illustrating the relationship between the vane opening degree of the first refrigerator and the vane opening degree of the second refrigerator in the refrigerator control method according to the first embodiment of the present disclosure. [Figure 9] FIG. 10 is a first flowchart showing an example of processing in a control method for a refrigerator according to a second embodiment of the present disclosure. [Figure 10] FIG. 10 is a second flowchart showing an example of processing in the refrigerator control method according to the second embodiment of the present disclosure. [Figure 11] FIG. 10 is a first explanatory diagram illustrating the relationship between the refrigeration capacity of a first refrigerator and the refrigeration capacity of a second refrigerator in a refrigerator control method according to a second embodiment of the present disclosure. [Figure 12] FIG. 10 is a second explanatory diagram illustrating the relationship between the refrigeration capacity of the first refrigerator and the refrigeration capacity of the second refrigerator in the refrigerator control method according to the second embodiment of the present disclosure. [Figure 13] FIG. 2 is a diagram illustrating an example of a hardware configuration of a computer included in the control device for the refrigerator according to each embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, each embodiment of the present disclosure will be described with reference to the drawings. In all drawings, the same or corresponding components are denoted by the same reference numerals, and common descriptions will be omitted.

[0013] First Embodiment Hereinafter, a chiller system 1 according to a first embodiment of the present disclosure will be described with reference to FIGS.

[0014] (Overall composition) FIG. 1 is a schematic diagram of a refrigerator system according to a first embodiment of the present disclosure. As shown in Fig. 1, the chiller system 1 according to this embodiment is configured such that cooling water, which is the object to be cooled, flows from an external device or the like, which is a load L, through a pipe 2, is cooled, and then returns to the load L. The pipe 2 is provided with a chilled water pump 3 and a first chiller 5A and a second chiller 5B connected in series, and the cooling water is pumped by the chilled water pump 3 and cooled through the first chiller 5A and the second chiller 5B. A sensor 4a that measures a chilled water inlet temperature t1 of the cooling water flowing through the pipe 2 and a flow meter 6 that measures a flow rate F of the cooling water flowing through the pipe 2 are provided upstream of the first chiller 5A. A sensor 4b that measures a chilled water outlet temperature t2 of the cooling water flowing through the pipe 2 is provided downstream of the second chiller 5B that is connected in series downstream of the first chiller 5A. The refrigeration capacity of each of the first and second refrigerators 5A and 5B is adjusted by the control device 10, and it is possible to switch between operation of only the first refrigerator 5A (single operation) and operation of both the first and second refrigerators 5A and 5B (multiple operation). In this embodiment, the single-unit operation is described as the operation of only the first refrigerator 5A, but the single-unit operation may also be the operation of only the second refrigerator 5B. That is, it is possible to switch between the operation of only the second refrigerator 5B (single-unit operation) and the operation of both the first refrigerator 5A and the second refrigerator 5B (multiple-unit operation). Furthermore, the refrigerator to be operated individually may be selected from either the first refrigerator 5A or the second refrigerator 5B depending on the situation. For example, after switching from operation of only the second refrigerator 5B (single operation) to operation of both the first refrigerator 5A and the second refrigerator 5B (multiple operation), the refrigerator may then be switched back to operation of only the first refrigerator 5A (single operation).

[0015] FIG. 2 is an explanatory diagram illustrating a first refrigerator and a second refrigerator connected in series in the refrigerator system. 2, the first refrigerator 5A includes an evaporator 501A, a condenser 502A, a compressor 503A, and an expansion valve 505A that constitute a refrigeration cycle. The refrigerant compressed by the compressor 503A is cooled by heat exchange with the cooling liquid flowing through the cooling liquid pipe 9 in the condenser 502A, condensed and liquefied to a liquid state, and then decompressed and expanded by the expansion valve 505A and supplied to the evaporator 501A. The supplied refrigerant exchanges heat with the cooling water to be cooled flowing through the pipe 2 in the evaporator 501A, cools the cooling water, evaporates, and then returns to the compressor 503A. The compressor 503A is provided with a compressor inlet vane 504A whose vane opening can be controlled by the control device 10. By adjusting the vane opening of the compressor inlet vane 504A, the flow rate of the refrigerant drawn into the compressor 503A can be changed, and the refrigeration capacity of the first refrigerator 5A can be controlled.

[0016] 2, the second refrigerator 5B connected in series downstream of the first refrigerator 5A includes an evaporator 501B, a condenser 502B, a compressor 503B, and an expansion valve 505B that form a refrigeration cycle similar to that of the first refrigerator 5A. The compressor 503B includes a compressor inlet vane 504B whose vane opening can be controlled by the control device 10. By adjusting the vane opening of compressor inlet vane 504B, the flow rate of refrigerant drawn into compressor 503B can be changed, and the refrigeration capacity of second refrigerator 5B can be controlled.

[0017] (Configuration of the refrigeration unit control device) FIG. 3 is a diagram illustrating a functional configuration of the control device for the refrigerator according to the first embodiment of the present disclosure. 3, the chiller control device 10 according to the first embodiment of the present disclosure includes a unit number increase / decrease control unit 11, a unit increase processing control unit 12, a unit decrease processing control unit 13, and a memory unit 17. The control device 10 can increase or decrease the number of operating chillers (5A, 5B) in accordance with a change in the load L.

[0018] The number increase / decrease control unit 11 adjusts the refrigeration capacity of each of the first refrigerator 5A and the second refrigerator 5B in accordance with changes in the load L, and controls switching between operation of only the first refrigerator 5A and operation of both the first refrigerator 5A and the second refrigerator 5B. In this embodiment, a higher-level device (not shown) detects a change in the load L, determines whether the number of operating chillers (5A, 5B) needs to be increased or decreased in response to an increase or decrease in the load, and notifies the number increase / decrease control unit 11 to increase or decrease the number of operating chillers if it is necessary. Based on the notification, the number increase / decrease control unit 11 controls the increase / decrease in the number of operating chillers (5A, 5B). Specifically, when only the first chiller unit 5A is operating and a notification is received that the load L has increased and an increase in the number of chillers is necessary, the unit count increase / decrease control unit 11 controls both the first chiller unit 5A and the second chiller unit 5B to increase the number of operating chillers. Also, when both the first chiller unit 5A and the second chiller unit 5B are operating and a notification is received that the load L has decreased and a decrease in the number of chillers is necessary, the unit count increase / decrease control unit 11 controls only the first chiller unit 5A to decrease the number of operating chillers.

[0019] When the load L increases and the number of refrigerators is increased from operating only the first refrigerator 5A to operating both the first refrigerator 5A and the second refrigerator 5B under the control of the number increase / decrease control unit 11, the additional unit processing control unit 12 controls the refrigeration capacity of the first refrigerator to be equal to or less than the refrigeration capacity at the start of the additional unit processing from the start of the additional unit processing to the completion of the additional unit processing.

[0020] When the load L decreases and the operation of the first refrigerator 5A and the second refrigerator 5B is reduced to only the first refrigerator 5A under the control of the number increase / decrease control unit 11, the unit reduction processing control unit 13 controls the refrigeration capacity of the first refrigerator to be equal to or greater than the refrigeration capacity at the start of the unit reduction processing from the start to the completion of the unit reduction processing.

[0021] The storage unit 17 stores various information necessary for the processes controlled by the number increase / decrease control unit 11, the increasing unit processing control unit 12, and the decreasing unit processing control unit 13.

[0022] (Process flow of the refrigerator control method) <Increase in unit processing> Hereinafter, the flow of processing in the control method by the control device 10 for the refrigerator according to this embodiment will be described with reference to FIGS. FIG. 4 is a flowchart showing an example of processing of a refrigerator control method according to the first embodiment of the present disclosure.

[0023] In this embodiment, the process shown in FIG. 4 is started, for example, when a higher-level device (not shown) detects a change in the load L, determines whether the number of operating chillers (5A, 5B) needs to be increased or decreased in response to an increase or decrease in the load L, and notifies the number increase / decrease control unit 11 of the control device 10 to increase or decrease the number of operating chillers. The process shown in Figure 4 may be started when the control device 10 itself determines that it is necessary to increase or decrease the number of operating vehicles, rather than when notified by a higher-level device, or may be executed regularly at other times.

[0024] The number increase / decrease control unit 11 is configured to perform processing other than the processing performed by the increase processing control unit 12 and the decrease processing control unit 13 described below, which is necessary when increasing or decreasing the number of operating chillers. For example, when only the first refrigerator 5A is operating, if the load L increases and a higher-level device (not shown) notifies the number increase / decrease control unit 11 to increase the number of refrigerators, the number increase / decrease control unit 11 will start an increase process to increase the number of refrigerators from only the first refrigerator 5A to both the first refrigerator 5A and the second refrigerator 5B.

[0025] In this case, as shown in FIG. 4, the operation is increased from only the first refrigerator 5A to both the first refrigerator 5A and the second refrigerator 5B (YES in step S101), so the additional refrigerator processing control unit 12 controls the refrigeration capacity of the first refrigerator 5A to be equal to or less than the refrigeration capacity at the start of the additional refrigerator processing from the start of the additional refrigerator processing to the completion of the additional refrigerator processing (step S102).

[0026] Specific processing in step S102 will be described below with reference to FIGS. 5 is a second flowchart showing an example of processing in the refrigerator control method according to the first embodiment of the present disclosure. In FIG. 5, steps S1021 to S1023 are described, which explain the specific processing in step S102. 7 is a first explanatory diagram illustrating the relationship between the vane opening of the first refrigerator and the vane opening of the second refrigerator in the refrigerator control method according to the first embodiment of the present disclosure. In this diagram, the horizontal axis represents time and the vertical axis represents vane opening, and specific examples of changes in the vane opening of the first refrigerator 5A and the second refrigerator 5B when the process of step S102 is performed are shown.

[0027] As shown in Figure 5, at the start of the additional unit processing (at the start of step S102), the additional unit processing control unit 12 sets the vane opening of the compressor inlet vane 504A of the first refrigerator 5A to a first vane opening that is equal to or less than the vane opening at the start of the additional unit processing (step S1021). The first vane opening is a value obtained by multiplying the vane opening at the start of the adding process by a predetermined parameter between 0 and 1, and in the example shown in Fig. 7, the first vane opening is set to a value obtained by multiplying the vane opening of 5A of the first refrigerator at the start of the adding process by the predetermined parameter of 0.5. The predetermined parameter by which the first vane opening is multiplied may be set to a value other than 0.5. Here, the predetermined parameter may be a constant value or may be a value that changes depending on conditions, for example, the predetermined parameter may be a value that changes depending on the vane opening.

[0028] As shown in Fig. 7, during the unit addition process, the vane opening of the compressor inlet vane 504A of the first refrigerator 5A approaches the set first vane opening. The time rate of change until the vane opening of the first refrigerator 5A reaches the set first vane opening (i.e., the slope at which the vane opening of the refrigerator 5A shown in Fig. 7 decreases from the start of the unit addition process until it reaches the first vane opening) depends on the motor that opens and closes the vane, and in this embodiment, for example, changes from fully open to fully closed over a period of 100 seconds. However, the time rate of change of the vane opening of the first refrigerator 5A may be other values.

[0029] When the vane opening of the compressor inlet vane 504A of the first refrigerator 5A reaches the set first vane opening, the vane opening is controlled to be maintained at the first vane opening. On the other hand, the vane opening of the compressor inlet vane 504B of the added second refrigerator 5B increases as the number of refrigerators increases, as shown in Fig. 7. The time rate of change when the vane opening of the second refrigerator 5B increases (i.e., the slope when the vane opening of the refrigerator 5B shown in Fig. 7 increases from the start of the number of refrigerators increasing) depends on the motor that opens and closes the vane, as with the first refrigerator 5A, but may be a value other than the time rate of change shown in Fig. 7.

[0030] When the vane opening of the second refrigerator becomes equal to or greater than the value obtained by adding a predetermined adjustment value to the first vane opening (YES in step S1022), the additional refrigerator processing control unit 12 cancels the setting of the vane opening of the first refrigerator (step S1023). The processing of step S1022 is repeated until the setting of the vane opening of the first refrigerator is canceled (NO in step S1022). The predetermined adjustment value described above may be either a positive or negative value, or may be zero. In this embodiment, the predetermined adjustment value is zero, but the predetermined adjustment value can be set to a value other than zero to make adjustments as needed. For example, if there is a difference in the rated capacity between the first refrigerator 5A and the second refrigerator 5B, the predetermined adjustment value can be set to a value other than zero to perform adjustment taking the difference in capacity into consideration. In the example shown in Fig. 7, when the additional unit process is completed, the vane opening of the second refrigerator is equal to the first vane opening plus the predetermined adjustment value of zero, so the additional unit process control unit 12 cancels the setting of the first refrigerator 5A, thereby completing the process flow in Fig. 5.

[0031] That is, the process of step S102 shown in Fig. 4, in which the additional unit process control unit 12 controls the refrigeration capacity of the first refrigerator 5A so that it is equal to or less than the refrigeration capacity at the start of the additional unit process from the start to the completion of the additional unit process, is completed. In the process thereafter, the refrigeration capacity of the first refrigerator 5A is controlled at least without being subject to restrictions by the additional unit process control unit 12. This completes the processing flow of FIG.

[0032] <Reduction in units> Next, a case will be described in which, while both the first chiller 5A and the second chiller 5B are operating, the load L decreases and a higher-level device (not shown) notifies the number increase / decrease control unit 11 to reduce the number of chillers. The number increase / decrease control unit 11 starts a reduction process to reduce the number of chillers from operating both the first chiller 5A and the second chiller 5B to operating only the first chiller 5A.

[0033] 4, since the number of chillers will not be increased (NO in step S101), the process proceeds to step S103. Since the operation of both the first chiller 5A and the second chiller 5B will be reduced to the operation of only the first chiller 5A (YES in step S103), the chiller reduction process control unit 13 controls the chiller capacity of the first chiller to be equal to or greater than the chiller capacity at the start of the chiller reduction process from the start to the completion of the chiller reduction process (step S104).

[0034] Specific processing in step S104 will be described below with reference to FIGS. Fig. 6 is a third flowchart showing an example of processing in the refrigerator control method according to the first embodiment of the present disclosure. Fig. 6 shows steps S1041 to S1043 that explain the specific processing in step S104. 8 is a first explanatory diagram illustrating the relationship between the vane opening of the first refrigerator and the vane opening of the second refrigerator in the refrigerator control method according to the first embodiment of the present disclosure. In this diagram, the horizontal axis represents time and the vertical axis represents vane opening, and specific examples of changes in the vane opening of the first refrigerator 5A and the second refrigerator 5B when the process of step S104 is performed are shown.

[0035] As shown in Figure 6, at the start of the unit reduction process (at the start of step S104), the unit reduction process control unit 13 sets the vane opening of the compressor inlet vane 504A of the first refrigerator 5A to a second vane opening that is equal to or greater than the vane opening at the start of the unit reduction process (step S1041). The second vane opening is a value obtained by multiplying the vane opening at the start of the unit reduction process by a predetermined parameter between 1 and 2, and in the example shown in Fig. 8, the second vane opening is set to a value obtained by multiplying the vane opening of 5A of the first refrigerator at the start of the unit reduction process by the predetermined parameter of 2.0. The predetermined parameter by which the second vane opening is multiplied may be set to a value other than 2.0. Here, the predetermined parameter may be a constant value or may be a value that changes depending on conditions, for example, the predetermined parameter may be a value that changes depending on the vane opening.

[0036] As shown in Fig. 8, during the unit reduction process, the vane opening of the compressor inlet vane 504A of the first refrigerator 5A approaches the set second vane opening. In this embodiment, the rate of change over time until the vane opening of the first refrigerator 5A reaches the set second vane opening (i.e., the slope at which the vane opening of the refrigerator 5A shown in Fig. 8 increases from the start of the unit reduction process until it reaches the second vane opening) depends on the motor that opens and closes the vane, as in the case of the unit increase process described above, but may be another value.

[0037] When the vane opening degree of the compressor inlet vane 504A of the first refrigerator 5A reaches the set second vane opening degree, it is thereafter adjusted in accordance with the chilled water outlet temperature t2. On the other hand, the vane opening of the compressor inlet vane 504B of the second refrigerator 5B to be reduced is reduced by the unit reduction process as shown in Fig. 8. In this embodiment, the time change rate at which the vane opening of the second refrigerator 5B is reduced (i.e., the slope at which the vane opening of the refrigerator 5B shown in Fig. 8 decreases from the start of the unit reduction process) depends on the motor that opens and closes the vane, as in the case of the unit addition process described above, but may be another value.

[0038] For example, when the unit reduction process is completed because the vane opening of the second refrigerator reaches a predetermined opening (YES in step S1042), the unit reduction process control unit 13 cancels the setting of the vane opening of the first refrigerator (step S1043). The process of step S1042 is repeated until the setting of the vane opening of the first refrigerator is canceled (NO in step S1042). In the example shown in Fig. 8, when the unit reduction process is completed, the vane opening of the second refrigerator reaches a predetermined opening, and the unit reduction process control unit 13 cancels the setting of the first refrigerator 5A, thereby completing the process flow in Fig. 6.

[0039] That is, the process of step S104 shown in Fig. 4, in which the unit reduction process control unit 13 controls the refrigeration capacity of the first refrigerator 5A to be equal to or greater than the refrigeration capacity at the start of the unit reduction process from the start to the completion of the unit reduction process, is completed. In the process thereafter, the refrigeration capacity of the first refrigerator 5A is controlled at least without being subject to the restriction by the unit reduction process control unit 13. This completes the processing flow of FIG.

[0040] (Action and effect) As described above, in this embodiment, the control device 10 that controls the first and second refrigerators 5A and 5B connected in series controls the refrigeration capacity of the first refrigerator 5A to be equal to or less than the refrigeration capacity at the start of the additional refrigerator processing when the operation is increased from the operation of only the first refrigerator 5A to the operation of the first and second refrigerators 5A and 5B in response to an increase in the load L.

[0041] In this way, when increasing the number of chillers from operating only the first chiller 5A to operating the first chiller 5A and the second chiller 5B, the additional chiller processing control unit 12 of the chiller control device 10 according to this embodiment performs feedforward control on the first chiller 5A, which is the first chiller, taking the additional chiller into consideration, to harmonize the overall chilling capacity with the second chiller 5B, which is the later chiller. This makes it possible to avoid a situation in which the overall chilling capacity of the first chiller 5A and the second chiller 5B becomes unstable when the chiller capacities of the first chiller 5A and the second chiller 5B are controlled individually without taking the additional chiller into consideration, resulting in instability in the chilled water outlet temperature t2 of the chilled water downstream of the first chiller 5A and the second chiller 5B. Furthermore, unlike conventional chiller control devices, the chiller capacity of the first chiller 5A is controlled without the need for additional components such as bypass piping and two-way valves, making it possible to stabilize the chilled water outlet temperature with a simple facility structure. In particular, this system can be applied to existing facilities, reducing installation costs.

[0042] Furthermore, according to one example of this embodiment, the additional unit processing control unit 12 may set the vane opening of the first refrigerator 5A to a first vane opening that is equal to or less than the vane opening at the start of the additional unit processing when the additional unit processing starts, and may cancel the setting of the vane opening of the first refrigerator when the vane opening of the second refrigerator 5B becomes equal to or greater than the first vane opening plus a predetermined adjustment value.

[0043] In this way, the chiller control device 10 according to this embodiment can stabilize the chilled water outlet temperature simply by adjusting the control of the vane opening in existing equipment. Furthermore, by setting a predetermined adjustment value, the chilled water outlet temperature t2 can be appropriately stabilized even if there is a difference in the rated capacity of the first chiller 5A and the second chiller 5B connected in series.

[0044] Furthermore, according to one example of this embodiment, when reducing the number of refrigerators from the first refrigerator 5A and the second refrigerator 5B to only the first refrigerator 5A in response to a decrease in load, the reduction processing control unit 13 may control the refrigeration capacity of the first refrigerator 5A to be equal to or greater than the refrigeration capacity at the start of the reduction processing from the start of the reduction processing to the completion of the reduction processing.

[0045] In this way, when reducing the number of chillers from the first chiller 5A and the second chiller 5B to only the first chiller 5A, the chiller reduction processing control unit 13 of the chiller control device 10 according to this embodiment performs feedforward control on the first chiller 5A in consideration of the reduction, thereby harmonizing the overall chilling capacity with the reduced second chiller 5B. This makes it possible to avoid a situation in which the overall chilling capacity of the first chiller 5A and the second chiller 5B becomes unstable when the chiller capacities of the first chiller 5A and the second chiller 5B are controlled individually without consideration of the reduction, resulting in instability of the chilled water outlet temperature t2 of the chilled water downstream of the first chiller 5A and the second chiller 5B. Furthermore, unlike conventional chiller control devices, the chiller capacity of the first chiller 5A is controlled without the need for additional components such as bypass piping and two-way valves, making it possible to stabilize the chilled water outlet temperature with a simple facility structure. In particular, this system can be applied to existing facilities, reducing installation costs.

[0046] Furthermore, according to one example of this embodiment, the unit reduction processing control unit 13 may set the vane opening of the first refrigerator 5A to a second vane opening that is equal to or greater than the vane opening at the start of the unit reduction processing when the unit reduction processing begins, and may cancel the setting of the vane opening of the first refrigerator 5A when the unit reduction processing is completed.

[0047] In this way, the chiller control device 10 according to this embodiment can stabilize the chilled water outlet temperature simply by adjusting the control of the vane opening degree in existing equipment.

[0048] According to one example of the present embodiment, the chiller system 1 according to the present embodiment may include the control device 10, a first chiller 5A, and a second chiller 5B.

[0049] In this way, the chiller system 1 according to this embodiment can be easily applied to existing equipment including a chiller control device, a first chiller, and a second chiller.

[0050] (Variation 1) In one example of this embodiment, the control device 10 is equipped with an increase in machine processing control unit 12 and a decrease in machine processing control unit 13, but as a variant, the control device 10 may be equipped with only either the increase in machine processing control unit 12 or the decrease in machine processing control unit 13.

[0051] By doing this, for example, in existing equipment where the chilled water outlet temperature is unlikely to become unstable when the number of units is reduced, but where the chilled water outlet temperature is likely to become unstable when the number of units is increased, more effective application can be achieved by implementing only the unit increase processing control unit 12. Similarly, for example, in existing equipment where the chilled water outlet temperature is likely to become unstable when the number of units is reduced, but where the chilled water outlet temperature is unlikely to become unstable when the number of units is increased, more effective application can be achieved by implementing only the unit reduction processing control unit 13. (Variation 2) In one example of this embodiment, the control device 10 is described as being equipped with a number increase / decrease control unit 11 that performs processing other than that performed by the unit increase processing control unit 12 and the unit decrease processing control unit 13, and is required when increasing or decreasing the number of operating chillers. However, the control device 10 may also be configured to be equipped with only the unit increase processing control unit 12 and the unit decrease processing control unit 13.

[0052] In this way, the chiller control device 10 according to this embodiment improves the processing capacity and facilitates implementation in existing equipment.

[0053] <Second embodiment> Hereinafter, a chiller system 1 according to a second embodiment of the present disclosure will be described with reference to FIGS. The configuration of the chiller system 1 and the functional configuration of the control device 10 according to the second embodiment of the present disclosure are similar to those of the first embodiment, and differ only in the points described below. The control method by the refrigerator control device 10 according to the second embodiment of the present disclosure differs from the control method by the refrigerator control device 10 according to the first embodiment shown in FIG. 4 only in the specific processing of steps S102 and S104.

[0054] (Process flow of the refrigerator control method according to the second embodiment) <Increase in unit processing> Specific processing for increasing the number of machines in the control method according to the second embodiment will be described below with reference to FIGS. 9 is a first flowchart showing an example of processing in a method for controlling a refrigerator according to a second embodiment of the present disclosure. In FIG. 9, steps S1025 to S1027 are described, which explain specific processing in step S102 shown in FIG. 11 is a first explanatory diagram illustrating the relationship between the refrigeration capacities of the first and second refrigerators in the refrigerator control method according to the second embodiment of the present disclosure. In this diagram, the horizontal axis represents time and the vertical axis represents refrigeration capacities, and specific examples of changes in the refrigeration capacities of the first and second refrigerators 5A and 5B when the process of step S102 is performed are shown.

[0055] In this embodiment, the refrigeration capacity of the chiller is calculated by (chilled water inlet temperature-chilled water outlet temperature) x flow rate x specific heat. For example, when calculating the refrigeration capacity of the first chiller 5A, the chilled water inlet temperature t1 measured by the sensor 4a and the flow rate F measured by the flow meter 6 are used. The chilled water outlet temperature of the first chiller 5A is not measured, but is estimated from the chilled water inlet temperature t1 measured by the sensor 4a, the chilled water outlet temperature t2 measured by the sensor 4b, the performance of the chiller 5A, the pressure of the evaporator 501A (measured by a sensor not shown), etc.

[0056] Similarly, for example, when calculating the refrigeration capacity of the second chiller 5B, the chilled water outlet temperature t2 measured by the sensor 4b and the flow rate F measured by the flow meter 6 are used. The chilled water inlet temperature of the second chiller 5B is not measured, but is estimated from the chilled water inlet temperature t1 measured by the sensor 4a, the chilled water outlet temperature t2 measured by the sensor 4b, the performance of the chiller 5B, and the pressure of the evaporator 501B (measured by a sensor not shown), etc.

[0057] As shown in Figure 9, at the start of the additional unit processing (at the start of step S102), the additional unit processing control unit 12 sets a target chilled water outlet temperature of the first chiller so that the ratio between the refrigeration capacity of the first chiller 5A and the refrigeration capacity of the second chiller 5B becomes a first ratio (step S1025). For example, when the predetermined refrigeration capacity parameter is set to be greater than or equal to 0 and less than or equal to 10, the first ratio is set as follows: refrigeration capacity of first refrigerator 5A: refrigeration capacity of second refrigerator 5B = (10 - predetermined refrigeration capacity parameter): predetermined refrigeration capacity parameter. In the example shown in Fig. 11, the predetermined refrigeration capacity parameter is set to 5.0. Note that the predetermined parameter for calculating the first ratio may be set to a value other than 5.0.

[0058] The number increase / decrease control unit 11 controls, for example, the vane opening of the expansion valves 505A and 505B, the rotation speed of the compressors 503A and 503B, etc., and controls the chilled water outlet temperature t2 measured by the sensor 4b to approach the target chilled water outlet temperature set by the unit increase processing control unit 12.

[0059] If the additional unit processing has not been completed (NO in step S1026), the additional unit processing control unit 12 adjusts the setting of the target chilled water outlet temperature of the first chiller so that, when the additional unit processing is completed, the ratio between the refrigeration capacity of the first chiller 5A and the refrigeration capacity of the second chiller 5B will ultimately be a value obtained by multiplying the ratio between the rated capacity of the first chiller and the rated capacity of the second chiller by a predetermined adjustment parameter (step S1027). In this embodiment, a case will be described in which the above-mentioned predetermined adjustment parameter is 1, but the predetermined adjustment parameter may be set to a value between 0 and 2, for example, as appropriate. The process of step S1027 is repeated until the machine addition process is completed (NO in step S1026). In this embodiment, based on the relationship Target refrigeration capacity = (chilled water inlet temperature - target chilled water outlet temperature) x flow rate x specific heat, the target chilled water outlet temperature is calculated and set so that the ratio between the target refrigeration capacity of the first chiller 5A and the target refrigeration capacity of the second chiller 5B is a value obtained by multiplying the ratio between the rated capacity of the first chiller 5A and the rated capacity of the second chiller 5B by a predetermined adjustment parameter.

[0060] As shown in FIG. 11, during the unit addition process, the refrigeration capacity of the first refrigerator 5A decreases while the refrigeration capacity of the second refrigerator 5B increases, and finally, when the unit addition process is completed, the ratio between the refrigeration capacity of the first refrigerator 5A and the refrigeration capacity of the second refrigerator 5B becomes the ratio between the rated capacity of the first refrigerator and the rated capacity of the second refrigerator. The additional machine processing control unit 12 ends the processing when the additional machine processing is completed (YES in step S1026), thereby completing the processing flow in FIG.

[0061] That is, the process of step S102 shown in Fig. 4, in which the additional unit process control unit 12 controls the refrigeration capacity of the first refrigerator 5A so that it is equal to or less than the refrigeration capacity at the start of the additional unit process from the start to the completion of the additional unit process, is completed. In the process thereafter, the refrigeration capacity of the first refrigerator 5A is controlled at least without being subject to restrictions by the additional unit process control unit 12. This completes the processing flow of FIG.

[0062] <Reduction in units> Next, a specific machine reduction process of the control method according to the second embodiment will be described with reference to FIGS. 10 is a second flowchart showing an example of processing in the method for controlling a refrigerator according to the second embodiment of the present disclosure. In FIG. 10, steps S1045 to S1047 are described, which explain the specific processing of step S104 shown in FIG. 12 is a second explanatory diagram illustrating the relationship between the refrigeration capacities of the first and second refrigerators in the refrigerator control method according to the second embodiment of the present disclosure. In this diagram, the horizontal axis represents time and the vertical axis represents refrigeration capacities, and specific examples of changes in the refrigeration capacities of the first and second refrigerators 5A and 5B when the process of step S104 is performed are shown.

[0063] As shown in Figure 10, at the start of the unit reduction process (at the start of step S104), the unit reduction process control unit 13 sets the target chilled water outlet temperature of the first chiller 5A so that the ratio between the refrigeration capacity of the first chiller 5A and the refrigeration capacity of the second chiller 5B becomes a value obtained by multiplying the ratio between the rated capacity of the first chiller 5A and the rated capacity of the second chiller 5B by a predetermined adjustment parameter (step S1045). In this embodiment, a case will be described in which the above-mentioned predetermined adjustment parameter is 1, but the predetermined adjustment parameter may be set to a value between 0 and 2, for example, as appropriate.

[0064] The number increase / decrease control unit 11 controls, for example, the vane opening of the expansion valves 505A and 505B, the rotation speed of the compressors 503A and 503B, etc., and controls the chilled water outlet temperature t2 measured by the sensor 4b to approach the target chilled water outlet temperature set by the unit increase processing control unit 12.

[0065] If the unit reduction process is not completed (NO in step S1046), the unit reduction process control unit 13 adjusts the setting of the target chilled water outlet temperature of the first chiller 5A so that the ratio between the refrigeration capacity of the first chiller 5A and the refrigeration capacity of the second chiller 5B will finally be the ratio between the rated capacity of the first chiller 5A and the rated capacity of the second chiller 5B multiplied by a predetermined reduction parameter when the unit reduction process is completed (step S1047). The process of step S1047 is repeated until the unit reduction process is completed (NO in step S1046). In this embodiment, the case will be described where the above-mentioned predetermined reduction parameter is 0, that is, the refrigeration capacity of the second refrigerator 5B is adjusted to zero, but the predetermined adjustment parameter may be set to, for example, a value greater than or equal to 0 and less than or equal to 0.3 as appropriate. In this embodiment, based on the relationship Target refrigeration capacity = (chilled water inlet temperature - target chilled water outlet temperature) x flow rate x specific heat, the target chilled water outlet temperature is calculated and set so that the ratio between the target refrigeration capacity of the first chiller 5A and the target refrigeration capacity of the second chiller 5B is the ratio between the rated capacity of the first chiller 5A and the value obtained by multiplying the rated capacity of the second chiller 5B by a predetermined reduction parameter.

[0066] As shown in Figure 12, during the unit reduction process, the refrigeration capacity of the first refrigerator 5A increases and the refrigeration capacity of the second refrigerator 5B decreases, and finally, when the unit reduction process is completed, the refrigeration capacity of the second refrigerator 5B becomes zero in the ratio between the target refrigeration capacity of the first refrigerator 5A and the target refrigeration capacity of the second refrigerator 5B. The machine reduction process control unit 13 ends the process when the machine reduction process is completed (YES in step S1046), thereby completing the process flow in FIG.

[0067] That is, the process of step S104 shown in Fig. 4, in which the unit reduction process control unit 13 controls the refrigeration capacity of the first refrigerator 5A to be equal to or greater than the refrigeration capacity at the start of the unit reduction process from the start to the completion of the unit reduction process, is completed. In the process thereafter, the refrigeration capacity of the first refrigerator 5A is controlled at least without being subject to the restriction by the unit reduction process control unit 13. This completes the processing flow of FIG.

[0068] (Action and effect) The control device 10 for controlling the first refrigerator 5A and the second refrigerator 5B connected in series according to the second embodiment of the present disclosure has the same functions and effects as those of the first embodiment. Furthermore, the control device 10 according to the second embodiment sets a target chilled water outlet temperature and continuously adjusts the target refrigeration capacity, thereby enabling delicate and reliable control until the unit increase or decrease process is completed. Furthermore, it is possible to accurately respond even when the rated capacities of the first and second refrigeration units are different.

[0069] <Hardware configuration> FIG. 13 is a diagram illustrating an example of a hardware configuration of a computer included in a control device for a refrigerator according to an embodiment of the present disclosure. As shown in FIG. 13, a computer 900 includes a processor 901 , a main memory device 902 , an auxiliary memory device 903 , and an interface 904 .

[0070] The control device 10 according to each of the above-described embodiments is implemented in a computer 900. The operation of each of the above-described processing units is stored in the form of a program in an auxiliary storage device 903. The processor 901 reads the program from the auxiliary storage device 903, loads it into the main storage device 902, and executes the above-described processing in accordance with the program. The processor 901 also allocates storage areas in the main storage device 902 corresponding to each of the above-described storage units in accordance with the program.

[0071] The program may be for realizing some of the functions to be performed by the computer 900. For example, the program may be combined with other programs already stored in the auxiliary storage device 903 or other programs implemented in other devices to perform the functions. In other embodiments, the computer 900 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions realized by the processor 901 may be realized by the integrated circuit.

[0072] Examples of the auxiliary storage device 903 include a magnetic disk, a magneto-optical disk, an optical disk, and a semiconductor memory. The auxiliary storage device 903 may be an internal medium directly connected to the bus of the computer 900, or may be an external storage device 910 connected to the computer 900 via the interface 904 or a communication line. Furthermore, when this program is distributed to the computer 900 via a communication line, the computer 900 that receives the program may load the program into the main storage device 902 and execute the above-described processing. In at least one embodiment, the auxiliary storage device 903 is a non-transitory tangible storage medium.

[0073] The program may also be for realizing part of the above-mentioned functions. Furthermore, the program may be a so-called differential file (differential program) that realizes the above-mentioned functions in combination with another program already stored in the auxiliary storage device 903.

[0074] <Modification> In the above embodiments, the first embodiment and the second embodiment are described separately, but the first embodiment and the second embodiment may be implemented simultaneously.

[0075] Furthermore, in the above embodiment, the refrigeration system 1 is configured to include only two refrigeration units, the first refrigeration unit 5A and the second refrigeration unit 5B, connected in series, but the refrigeration system 1 may also include three or more refrigeration units connected in series. In this case, the above-described embodiment of the present invention may be applied by regarding each of the three or more refrigerators as two refrigerator groups.

[0076] Furthermore, in the above embodiment, the case where one flow meter 6 is provided to measure the flow rate F of the cooling water flowing through the pipe 2 has been described, but two or more flow meters may be provided. In addition, in the above embodiment, a case has been described in which only two sensors are provided: sensor 4a that measures the chilled water inlet temperature t1 of the cooling water flowing through pipe 2, and sensor 4b that measures the chilled water outlet temperature t2 of the cooling water flowing through pipe 2; however, two or more sensors may be provided. For example, a sensor may be provided downstream of the first chiller 5A to measure the chilled water outlet temperature of the chiller 5A of the cooling water flowing through the pipe 2. Also, a sensor may be provided upstream of the second chiller 5B to measure the chilled water inlet temperature of the cooling water flowing through the pipe 2 of the chiller 5B. Furthermore, in the second embodiment described above, the temperatures measured by these sensors may be used to calculate the chilling capacities of the first chiller 5A and the second chiller 5B.

[0077] <Other embodiments> Although several embodiments of the present disclosure have been described above, these embodiments are presented as examples and are not intended to limit the scope of the present disclosure. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit and scope of the present disclosure. These embodiments and their modifications are included within the scope and spirit of the disclosure.

[0078] <Additional Notes> The refrigerator control device, refrigerator system, refrigerator control method, and program described in each embodiment can be understood, for example, as follows.

[0079] (1) According to the first aspect, the refrigerator control device 10 is a control device 10 that controls a first refrigerator 5A and a second refrigerator 5B connected in series, and is equipped with an additional unit processing control unit 12 that, when increasing the operation from the first refrigerator 5A alone to the first refrigerator 5A and the second refrigerator 5B in response to an increase in load, controls the refrigeration capacity of the first refrigerator 5A to be equal to or less than the refrigeration capacity at the start of the additional unit processing from the start of the additional unit processing to the completion of the additional unit processing.

[0080] In this way, when increasing the number of chillers from operating only the first chiller 5A to operating the first chiller 5A and the second chiller 5B, the additional chiller processing control unit 12 of the chiller control device 10 according to this embodiment performs feedforward control on the first chiller 5A, which is the first chiller, taking the increase into consideration, to harmonize the overall chilling capacity with the second chiller 5B, which is the later chiller. This makes it possible to avoid a situation in which the overall chilling capacity of the first chiller 5A and the second chiller 5B becomes unstable when the chiller capacities of the first chiller 5A and the second chiller 5B are controlled individually without taking the increase into consideration, resulting in instability of the chilled water outlet temperature t2 of the chilled water downstream of the first chiller 5A and the second chiller 5B. Furthermore, unlike conventional chiller control devices, the chiller capacity of the first chiller 5A is controlled without the need for additional components such as bypass piping and two-way valves, making it possible to stabilize the chilled water outlet temperature with a simple facility structure. In particular, this system can be applied to existing facilities, reducing installation costs.

[0081] (2) According to the second aspect, in the refrigerator control device 10 according to the first aspect, the additional unit processing control unit 12 sets the vane opening of the first refrigerator 5A to a first vane opening that is equal to or less than the vane opening at the start of the additional unit processing when the additional unit processing starts, and when the vane opening of the second refrigerator 5B becomes equal to or greater than the first vane opening plus a predetermined adjustment value, cancels the setting of the vane opening of the first refrigerator 5A.

[0082] In this way, the chiller control device 10 according to this embodiment can stabilize the chilled water outlet temperature simply by adjusting the control of the vane opening in existing equipment. Furthermore, by setting a predetermined adjustment value, the chilled water outlet temperature t2 can be appropriately stabilized even if there is a difference in the rated capacity of the first chiller 5A and the second chiller 5B connected in series.

[0083] (3) According to the third aspect, the control device 10 for the chiller according to the first or second aspect further includes a reduction processing control unit 13 that, when reducing the number of chillers from operating the first chiller 5A and the second chiller 5B to operating only the first chiller 5A in response to the reduction in load, controls the chiller capacity of the first chiller 5A to be equal to or greater than the chiller capacity at the start of the reduction processing from the start of the reduction processing to the completion of the reduction processing.

[0084] In this way, when reducing the number of chillers from the first chiller 5A and the second chiller 5B to only the first chiller 5A, the chiller reduction processing control unit 13 of the chiller control device 10 according to this embodiment performs feedforward control on the first chiller 5A in consideration of the reduction, thereby harmonizing the overall chilling capacity with the reduced second chiller 5B. This makes it possible to avoid a situation in which the overall chilling capacity of the first chiller 5A and the second chiller 5B becomes unstable when the chiller capacities of the first chiller 5A and the second chiller 5B are controlled individually without consideration of the reduction, resulting in instability of the chilled water outlet temperature t2 of the chilled water downstream of the first chiller 5A and the second chiller 5B. Furthermore, unlike conventional chiller control devices, the chiller capacity of the first chiller 5A is controlled without the need for additional components such as bypass piping and two-way valves, making it possible to stabilize the chilled water outlet temperature with a simple facility structure. In particular, this system can be applied to existing facilities, reducing installation costs.

[0085] (4) According to the fourth aspect, in the refrigerator control device 10 according to the third aspect, at the start of the unit reduction process, the vane opening of the first refrigerator 5A is set to a second vane opening that is equal to or greater than the vane opening at the start of the unit reduction process, and at the completion of the unit reduction process, the vane opening setting of the first refrigerator 5A is released.

[0086] In this way, the chiller control device 10 according to this embodiment can stabilize the chilled water outlet temperature simply by adjusting the control of the vane opening degree in existing equipment.

[0087] (5) According to the fifth aspect, in the chiller control device 10 relating to any one of the first to fourth aspects, the unit increase processing control unit 12 sets a target chilled water outlet temperature of the first chiller 5A so that the ratio between the chilling capacity of the first chiller 5A and the chilling capacity of the second chiller 5B becomes a first ratio at the start of the unit increase processing, and adjusts the setting of the target chilled water outlet temperature of the first chiller 5A so that the ratio between the chilling capacity of the first chiller 5A and the chilling capacity of the second chiller 5B becomes a value obtained by multiplying a predetermined adjustment parameter by the ratio between the rated capacity of the first chiller 5A and the rated capacity of the second chiller 5B at the completion of the unit increase processing.

[0088] In this way, the chiller control device 10 according to this embodiment can continuously adjust the target chilled water outlet temperature and adjust the target chilling capacity, thereby enabling delicate and reliable control until the unit increase or decrease process is completed. Furthermore, it can accurately respond even when the rated capacities of the first chiller and the second chiller are different.

[0089] (6) According to a sixth aspect, in the chiller control device 10 according to any one of the third to fifth aspects, the unit reduction process control unit 13 sets a target chilled water outlet temperature of the first chiller 5A so that, at the start of the unit reduction process, the ratio between the chilling capacity of the first chiller 5A and the chilling capacity of the second chiller 5B becomes a value obtained by multiplying the ratio between the rated capacity of the first chiller 5A and the rated capacity of the second chiller 5B by a predetermined adjustment parameter, and finally adjusts the setting of the target chilled water outlet temperature of the first chiller 5A so that, at the completion of the unit reduction process, the ratio between the chilling capacity of the first chiller 5A and the chilling capacity of the second chiller 5B becomes a value obtained by multiplying the rated capacity of the first chiller 5A and the rated capacity of the second chiller 5B by a predetermined reduction parameter.

[0090] In this way, the chiller control device 10 according to this embodiment can continuously adjust the target chilled water outlet temperature and adjust the target chilling capacity, thereby enabling delicate and reliable control until the unit increase or decrease process is completed. Furthermore, it can accurately respond even when the rated capacities of the first chiller and the second chiller are different.

[0091] (7) According to a seventh aspect, a chiller system includes the control device 10 according to any one of the first to sixth aspects, the first chiller 5A, and the second chiller 5B.

[0092] In this way, the chiller system 1 according to this embodiment can be easily applied to existing equipment including a chiller control device, a first chiller, and a second chiller.

[0093] (8) According to an eighth aspect, a method for controlling a refrigerator is a control method for controlling a first refrigerator 5A and a second refrigerator 5B connected in series, and includes a step of controlling, when increasing the operation from only the first refrigerator 5A to both the first refrigerator 5A and the second refrigerator 5B in response to an increase in load, such that the refrigeration capacity of the first refrigerator 5A is equal to or less than the refrigeration capacity at the start of the additional refrigerator processing from the start of the additional refrigerator processing to the completion of the additional refrigerator processing.

[0094] In this way, in the chiller control method according to this embodiment, when increasing the number of chillers from operating only the first chiller 5A to operating the first chiller 5A and the second chiller 5B, feedforward control is performed on the first chiller 5A, which is the first chiller, in consideration of the increase in the number of chillers, to harmonize the overall chilling capacity with the second chiller 5B, which is the later chiller. This makes it possible to avoid a situation in which the overall chilling capacity of the first chiller 5A and the second chiller 5B becomes unstable when the chiller capacities of the first chiller 5A and the second chiller 5B are controlled individually without consideration of the increase in the number of chillers, resulting in instability of the chilled water outlet temperature t2 of the chilled water downstream of the first chiller 5A and the second chiller 5B. Furthermore, unlike conventional technology, the refrigeration capacity of the first chiller 5A is controlled without the need for additional components such as bypass piping and two-way valves, so the chilled water outlet temperature can be stabilized with a simple facility structure. In particular, this system can be applied to existing facilities, and installation costs can be reduced.

[0095] (9) According to the ninth aspect, in the method for controlling a refrigerator according to the eighth aspect, when the operation of the first refrigerator 5A and the second refrigerator 5B is reduced to the operation of only the first refrigerator 5A in response to the reduction in the load, the method further includes a step of controlling the refrigeration capacity of the first refrigerator 5A to be equal to or greater than the refrigeration capacity at the start of the reduction process from the start of the reduction process to the completion of the reduction process.

[0096] In this way, the chiller control method according to this embodiment can stabilize the chilled water outlet temperature by simply adjusting the vane opening control in existing equipment. Furthermore, by setting a predetermined adjustment value, the chilled water outlet temperature t2 can be appropriately stabilized even if there is a difference in the rated capacity of the first chiller 5A and the second chiller 5B connected in series.

[0097] (10) According to the tenth aspect, the program causes the computer 900 of the control device 10, which controls the first and second refrigerators 5A and 5B connected in series, to execute a step of controlling the refrigeration capacity of the first refrigerator 5A to be equal to or less than the refrigeration capacity at the start of the additional refrigerator processing from the start of the additional refrigerator processing until the completion of the additional refrigerator processing when the operation is increased from the operation of the first refrigerator 5A alone to the operation of the first refrigerator 5A and the second refrigerator 5B in response to an increase in load.

[0098] In this way, when increasing the number of chillers from operating only the first chiller 5A to operating the first chiller 5A and the second chiller 5B, the program according to this embodiment performs feedforward control on the first chiller 5A, which is the first chiller, taking into account the increase in the number of chillers, to harmonize the overall chilling capacity with the second chiller 5B, which is the later chiller. This makes it possible to avoid a situation in which the overall chilling capacity of the first chiller 5A and the second chiller 5B becomes unstable when the chiller capacities of the first chiller 5A and the second chiller 5B are controlled individually without taking into account the increase in the number of chillers. Furthermore, unlike conventional technology, the refrigeration capacity of the first chiller 5A is controlled without the need for additional components such as bypass piping and two-way valves, so the chilled water outlet temperature can be stabilized with a simple facility structure. In particular, this system can be applied to existing facilities, and installation costs can be reduced.

[0099] (11) According to the eleventh aspect, in the program according to the tenth aspect, when the operation of the first and second refrigerators 5A and 5B is reduced to the operation of only the first refrigerator 5A in response to the reduction in the load, the program further executes a step of controlling the refrigeration capacity of the first refrigerator 5A to be equal to or greater than the refrigeration capacity at the start of the reduction process from the start of the reduction process to the completion of the reduction process.

[0100] In this way, the program according to this embodiment can stabilize the chilled water outlet temperature t2 in existing equipment simply by adjusting the control of the vane opening. Furthermore, by setting a predetermined adjustment value, the chilled water outlet temperature t2 can be appropriately stabilized even if there is a difference in the rated capacity of the first chiller 5A and the second chiller 5B connected in series. [Explanation of symbols]

[0101] 1. Refrigeration system 2 Piping 3. Chilled water pump 4a, 4b sensors 5A First refrigerator 5B Second refrigerator 6 Flowmeter 9 Coolant piping 10 Control device 11 Number increase / decrease control unit 12 Additional unit processing control unit 13 Reduced unit processing control unit 17 Memory section 501A, 501B evaporators 502A, 502B Condenser 503A, 503B compressors 504A, 504B Compressor inlet vanes 505A, 505B Expansion Valve 900 Computers 901 processor 902 Main storage 903 Auxiliary storage device 904 Interface 910 External storage device L load (external device)

Claims

1. A control device that controls a first refrigerator and a second refrigerator connected in series, an additional unit processing control unit that, when increasing the number of units from the operation of only the first refrigerator to the operation of the first refrigerator and the second refrigerator in response to an increase in load, controls the refrigeration capacity of the first refrigerator to be equal to or less than the refrigeration capacity at the start of the additional unit processing from the start of the additional unit processing to the completion of the additional unit processing; A control device for a refrigerator comprising:

2. 2. The refrigerator control device according to claim 1, wherein the unit increase processing control unit sets the vane opening of the first refrigerator to a first vane opening that is equal to or less than the vane opening at the start of the unit increase processing when the unit increase processing starts, and cancels the setting of the vane opening of the first refrigerator when the vane opening of the second refrigerator becomes equal to or greater than a value obtained by adding a predetermined adjustment value to the first vane opening.

3. a unit reduction processing control unit that, when reducing the number of units from operation of the first and second chillers to operation of only the first chiller in response to the reduction in the load, controls the refrigeration capacity of the first chiller so that it is equal to or greater than the refrigeration capacity at the start of the unit reduction processing from the start of the unit reduction processing to the completion of the unit reduction processing; The control device for a refrigerator according to claim 1 or 2, further comprising:

4. 4. The refrigerator control device according to claim 3, wherein the unit reduction process control unit sets the vane opening of the first refrigerator to a second vane opening that is equal to or greater than the vane opening at the start of the unit reduction process when the unit reduction process is started, and cancels the setting of the vane opening of the first refrigerator when the unit reduction process is completed.

5. 2. The chiller control device according to claim 1, wherein the unit increase processing control unit sets a target chilled water outlet temperature of the first chiller such that a ratio between the chilling capacity of the first chiller and the chilling capacity of the second chiller becomes a first ratio at the start of the unit increase processing, and adjusts the setting of the target chilled water outlet temperature of the first chiller such that, at the completion of the unit increase processing, the ratio between the chilling capacity of the first chiller and the chilling capacity of the second chiller becomes a value obtained by multiplying a ratio between a rated capacity of the first chiller and a rated capacity of the second chiller by a predetermined adjustment parameter.

6. 4. The chiller control device according to claim 3, wherein the unit reduction process control unit sets a target chilled water outlet temperature of the first chiller so that, at the start of the unit reduction process, a ratio between the chilling capacity of the first chiller and the chilling capacity of the second chiller becomes a value obtained by multiplying a ratio between a rated capacity of the first chiller and a rated capacity of the second chiller by a predetermined adjustment parameter, and finally adjusts the setting of the target chilled water outlet temperature of the first chiller so that, at the completion of the unit reduction process, the ratio between the chilling capacity of the first chiller and the chilling capacity of the second chiller becomes a ratio between the rated capacity of the first chiller and a value obtained by multiplying the rated capacity of the second chiller by a predetermined reduction parameter.

7. The control device according to claim 1 or 2; the first refrigerator; the second refrigerator; A refrigerator system comprising:

8. A control method for controlling a first refrigerator and a second refrigerator connected in series, comprising: a step of controlling, when increasing the number of refrigerators from only the first refrigerator to both the first and second refrigerators in response to an increase in load, the refrigeration capacity of the first refrigerator to be equal to or less than the refrigeration capacity at the start of the additional refrigerator processing from the start of the additional refrigerator processing to the completion of the additional refrigerator processing; A method for controlling a refrigerator having the above structure.

9. a step of controlling, in the case of reducing the number of chillers from operation of the first chiller and the second chiller to operation of only the first chiller in response to the reduction in the load, the refrigeration capacity of the first chiller to be equal to or greater than the refrigeration capacity at the start of the reduction process from the start of the reduction process to the completion of the reduction process; The method of claim 8 further comprising:

10. a computer of a control device that controls the first refrigerator and the second refrigerator connected in series; a step of controlling, when increasing the number of refrigerators from only the first refrigerator to both the first and second refrigerators in response to an increase in load, the refrigeration capacity of the first refrigerator to be equal to or less than the refrigeration capacity at the start of the additional refrigerator processing from the start of the additional refrigerator processing to the completion of the additional refrigerator processing; A program that executes the following.

11. a step of controlling, in the case of reducing the number of chillers from operation of the first chiller and the second chiller to operation of only the first chiller in response to the reduction in the load, the refrigeration capacity of the first chiller to be equal to or greater than the refrigeration capacity at the start of the reduction process from the start of the reduction process to the completion of the reduction process; The program according to claim 10, further comprising:

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