Cooling system, cooling method and control device

Abstract

To reduce power consumption associated with cooling of a server device SV. [Solution] The cooling system S of this embodiment has a first flow path through which cooling water circulates to cool the cooling liquid by exchanging heat with the cooling liquid for cooling the server device SV, a second flow path branching off from the first flow path and provided with a cooling device 23 for cooling part of the cooling water, and a control device 3 that controls, depending on the temperature of the cooling water flowing through the first flow path, the flow rate of cooling water circulating through the first flow path without flowing from the first flow path to the second flow path and the flow rate of cooling water flowing from the first flow path into the second flow path, being cooled by the cooling device 23, and then returning to the first flow path.

Description

[Technical field]

[0001] The present invention relates to a cooling system, a cooling method, and a control device for cooling a server device. [Background technology]

[0002] 2. Description of the Related Art There is known a cooling system in which cooling water, the temperature of which has been increased by heat exchange with a refrigerant, is cooled by a cooling tower (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2024-173281 A Summary of the Invention [Problem to be solved by the invention]

[0004] The cooling water that exchanges heat with the coolant for cooling the server devices gradually rises in temperature due to the heat exchange, and therefore needs to be cooled by a cooling device. However, in conventional cooling systems, the cooling water is sent to the cooling device even when the coolant is at a temperature range that allows the server devices to function, which causes a problem of large power consumption for transporting the cooling water.

[0005] The present invention has been made in consideration of these points, and has an object to reduce the power consumption associated with cooling a server device. [Means for solving the problem]

[0006] A cooling system according to a first aspect of the present invention comprises a first flow path through which cooling water circulates to cool a cooling liquid for cooling a server device by exchanging heat with the cooling liquid, a second flow path branching off from the first flow path and provided with a cooling device for cooling a portion of the cooling water, and a control device for controlling, depending on the temperature of the cooling water flowing through the first flow path, a flow rate of the cooling water circulating through the first flow path without flowing from the first flow path to the second flow path, and a flow rate of the cooling water flowing from the first flow path into the second flow path, being cooled by the cooling device, and then returning to the first flow path.

[0007] The control device may control the flow rate of the cooling water by controlling the flow of the cooling water so that the cooling water circulates within the first flow path without flowing from the first flow path to the second flow path when the temperature of the cooling water flowing through the first flow path is less than a first threshold value, and control the flow rate of the cooling water by controlling the flow of the cooling water so that the cooling water flows from the first flow path to the second flow path and the cooling water that has flowed into the second flow path returns to the first flow path after being cooled by the cooling device when the temperature of the cooling water flowing through the first flow path is equal to or higher than the first threshold value.

[0008] The second flow path may be provided with a second pump for flowing the cooling water through the second flow path, and the control device may relatively reduce the operating amount of the second pump when the temperature of the cooling water flowing through the first flow path is less than a first threshold value, and relatively increase the operating amount of the second pump when the temperature of the cooling water flowing through the first flow path is equal to or higher than the first threshold value.

[0009] The first flow path may be provided with a first valve for controlling the flow rate of the cooling water circulating within the first flow path, and the second flow path may be provided with a second valve for controlling the flow rate of the cooling water flowing from the first flow path to the second flow path and a third valve for controlling the flow rate of the cooling water flowing from the second flow path to the first flow path, and the control device may control the flow rate of the cooling water by controlling the states of the first valve, the second valve, and the third valve.

[0010] The control device may control the opening and closing states of the first valve, the second valve, and the third valve so that the first valve is open and the second valve and the third valve are closed when the temperature of the cooling water flowing through the first flow path is less than a first threshold, and control the opening and closing states of the first valve, the second valve, and the third valve so that the first valve is closed and the second valve and the third valve are open when the temperature of the cooling water flowing through the first flow path is equal to or higher than the first threshold.

[0011] The first flow path may be provided with a first pump for flowing the cooling water through the first flow path, and a heat exchanger for exchanging heat between the cooling liquid and the cooling water, and the control device may control the flow rate of the cooling water flowing through the first flow path by controlling the operation of the first pump based on a temperature difference between the temperature of the cooling water flowing into the heat exchanger and the temperature of the cooling water flowing out of the heat exchanger.

[0012] When the temperature difference is less than a second threshold value, the control device may control an operation of the first pump so that a flow velocity of the cooling water flowing through the first flow path is reduced.

[0013] The control device may control an operation of the first pump so that a flow rate of the cooling water flowing through the first flow path increases when the temperature difference is equal to or greater than a third threshold value that is greater than the second threshold value.

[0014] The control device may control a flow rate of the cooling water flowing through the flow passage based on a temperature of the cooling water flowing through the flow passage.

[0015] At least one of the first flow path and the second flow path may be provided with a pump that controls the flow rate of the cooling water flowing through the flow path, and the control device may control the operation of the pump at a minimum power value required to achieve a flow rate of the cooling water that can keep the temperature of the cooling water after heat exchange between the cooling water and the cooling liquid within a predetermined range.

[0016] The control device may determine the minimum power value based on the predicted power required by the pump output by a machine learning model that has been trained by machine learning using as training data the temperature of the cooling water after the cooling water has exchanged heat with the cooling liquid and the power consumption of the pump required to bring the cooling water to that temperature, by inputting the specified range of the cooling water temperature into the machine learning model.

[0017] The control device may calculate the reduced power due to the circulation by subtracting the power consumption when the flow of the cooling water is controlled so that the cooling water that flows into the second flow path returns to the first flow path after being cooled by the cooling device for a predetermined period of time from the power consumption when the flow of the cooling water is controlled so that the cooling water does not flow from the first flow path to the second flow path and circulates within the first flow path, and output the calculated reduced power.

[0018] The first flow path may be provided with a water tank for storing the cooling water in an amount larger than the capacity of the first flow path.

[0019] A cooling method according to a second aspect of the present invention is executed by a computer and includes a step of controlling, in accordance with a temperature of the cooling water flowing through a first flow path through which cooling water circulates to cool a cooling liquid for cooling a server device by heat exchange with the cooling liquid, a flow rate of the cooling water that branches off from the first flow path and circulates through the first flow path without flowing from the first flow path into a second flow path provided with a cooling device for cooling a portion of the cooling water, and a flow rate of the cooling water that flows from the first flow path into the second flow path, is cooled by the cooling device, and then returns to the first flow path.

[0020] A control device according to a third aspect of the present invention controls, in accordance with the temperature of the cooling water flowing through a first flow path through which cooling water circulates to cool a cooling liquid for cooling a server device by heat exchange with the cooling liquid, the flow rate of the cooling water that branches off from the first flow path and circulates through the first flow path without flowing from the first flow path into a second flow path in which a cooling device for cooling part of the cooling water is provided, and the flow rate of the cooling water that flows from the first flow path into the second flow path, is cooled by the cooling device, and then returns to the first flow path. Effect of the Invention

[0021] The present invention provides an advantage that the power consumption involved in cooling a server device can be reduced. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is a diagram showing an overview of the operation of the cooling system S. [Diagram 2] FIG. 2 is a diagram illustrating an example of the configuration of a control device 3. [Diagram 3] FIG. 11 illustrates an example of a state management table. [Figure 4] FIG. 13 is a diagram illustrating an example of a power recording table. [Diagram 5] 4 is a flowchart showing the flow of processing executed by the control device 3. [Figure 6] 10 is a flowchart showing a process for opening the second flow path by a continuous control method. [Figure 7] FIG. 13 is a diagram showing an outline of the operation of the cooling system S in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] [Outline of Information Processing System S] 1 is a diagram showing an outline of the operation of the cooling system S. The cooling system S is a system that controls the flow rate of the cooling water so that the cooling device 23 can cool a part of the cooling water when the temperature of the cooling water that exchanges heat with the coolant for cooling the server device SV increases.

[0024] The cooling system S has a first flow path through which the cooling water circulates, a second flow path in which a cooling device 23 is provided, and a control device 3 that controls the flow rate of the cooling water. The control device 3 controls, according to the temperature of the cooling water flowing through the first flow path, the flow rate of the cooling water circulating through the first flow path without flowing from the first flow path to the second flow path, and the flow rate of the cooling water flowing from the first flow path into the second flow path, being cooled by the cooling device 23, and then returning to the first flow path.

[0025] As an example, when the temperature of the cooling water flowing in the first flow path is below a threshold value, the control device 3 controls the flow of the cooling water so that the cooling water circulates in the first flow path without flowing into the second flow path. On the other hand, when the temperature of the cooling water flowing in the first flow path is equal to or higher than the threshold value, the control device 3 controls the flow of the cooling water so that the cooling water flows from the first flow path into the second flow path, and the cooling water that has flowed into the second flow path is cooled by the cooling device 23 and then returns to the first flow path. The flow of the process executed by the cooling system S will be specifically described below.

[0026] The cooling liquid, whose temperature has increased by absorbing heat radiated by the server devices SV (the number of which is not limited), flows into the secondary side of a cooling distribution unit (CDU 13) that functions as a heat exchanger. Meanwhile, the cooling water in a water tank 14 provided in the first flow path is discharged from the water tank 14 by the power of a first pump 12. The cooling water discharged from the water tank 14 circulates in the first flow path as a first valve 11 provided in the first flow path is opened and a second valve 211 and a third valve 212 provided in the second flow path are closed. The cooling water circulating in the first flow path flows into the primary side of the CDU 13.

[0027] The heat of the cooling liquid, which has risen in temperature and flowed into the secondary side of the CDU 13, is transferred to the cooling water, which has flowed into the primary side of the CDU 13. In this way, heat is exchanged between the cooling liquid and the cooling water, so that the temperature of the cooling water circulating in the first flow path gradually rises.

[0028] The control device 3 periodically acquires the temperature of the cooling water circulating in the first flow path. When the acquired temperature of the cooling water is equal to or higher than a threshold value (e.g., 45°C), the control device 3 controls the opening and closing states of the first valve 11, the second valve 211, and the third valve 212 so that the first valve 11 is closed and the second valve 211 and the third valve 212 are open. The control device 3 also operates the second pump 22 provided in the second flow path.

[0029] As a result, the cooling water whose temperature is equal to or higher than the threshold flows into the second flow path via the second valve 211. The cooling water that has flowed into the second flow path flows into the cooling device 23 in a state where it has been cooled to a first predetermined temperature (for example, 18°C ​​to 35°C) by the influence of the outside air or the like before flowing into the cooling device 23. Then, the cooling water that has been cooled by the cooling device 23 to a second predetermined temperature (for example, 15°C to 29°C) that is lower than the first predetermined temperature is discharged from the cooling device 23 by the power of the second pump 22 and returns to the first flow path via the third valve 212. In this manner, the cooling water circulating in the first flow path is cooled.

[0030] When the temperature of the cooling water circulating in the first flow path falls below the threshold, the control device 3 controls the opening and closing states of the first valve 11, the second valve 211, and the third valve 212 so that the first valve 11 opens again and the second valve 211 and the third valve 212 close again. As a result, the cooling water again circulates in the first flow path without flowing into the second flow path. In addition, when the temperature of the cooling water circulating in the first flow path falls below the threshold, the control device 3 controls the second pump 22 provided in the second flow path so as not to operate.

[0031] As described above, when the temperature of the cooling water flowing through the first flow path is below the threshold value, the control device 3 controls the flow of the cooling water so that the cooling water circulates through the first flow path without flowing into the second flow path, and does not operate the second pump 22 provided in the second flow path. As a result, compared to a conventional cooling system that sends cooling water to the cooling device even when the cooling liquid is in a temperature range that allows the server device to function, the cooling system S can reduce power consumption associated with cooling the server device SV. Below, the configurations of the first flow path, the second flow path, and the control device 3 of the cooling system S will be described.

[0032] [Configuration of the first flow path] The first flow path is a flow path through which cooling water circulates to cool the cooling liquid for cooling the server device SV by exchanging heat with the cooling liquid. The shape of the first flow path may be any shape as long as the cooling water can circulate. The first flow path is provided with a first valve 11, a first pump 12, a CDU 13, and a water tank 14. The first valve 11, the first pump 12, the CDU 13, and the water tank 14 are capable of transmitting and receiving data to and from the control device 3.

[0033] The first valve 11 is a valve for controlling the flow rate of the cooling water circulating in the first flow path. The method by which the first valve 11 controls the flow rate of the cooling water may be an ON-OFF control method in which the flow rate of the cooling water is controlled by setting the valve opening to "fully open" or "fully closed," or a continuous control method in which the flow rate of the cooling water is controlled by continuously changing the valve opening. When the control method is the ON-OFF control method, the first valve 11 is a valve for switching between a state in which the cooling water circulates in the first flow path and a state in which it does not circulate.

[0034] The first pump 12 is a pump for causing the cooling water to flow through the first flow path. The first pump 12 causes the cooling water to flow through the first flow path by, for example, discharging the cooling water stored in a water tank 14 (described later) from the water tank 14 using its power.

[0035] The CDU 13 functions as a heat exchanger for exchanging heat between the cooling liquid for cooling the server devices SV and the cooling water for cooling the cooling liquid. As described above, the heat of the cooling liquid that flows into the secondary side of the CDU 13 is transferred to the cooling water that flows into the primary side of the CDU 13, whereby heat is exchanged between the cooling liquid and the cooling water.

[0036] The water tank 14 is a tank or the like for storing a larger amount of cooling water than the capacity of the first flow path. The cooling water stored in the water tank 14 is discharged from the water tank 14 by the power of the first pump 12, and then circulates through the first flow path and flows into the water tank 14. The water tank 14 is, for example, a sealed water tank in which the tank is sealed and filled with cooling water. By making the water tank 14 a sealed water tank, the cooling water does not come into contact with the air, making it possible to prevent oxidation corrosion of the piping and facility equipment.

[0037] The higher the temperature of the outside air, the easier it is for the cooling water to be warmed by the outside air. Therefore, the higher the temperature of the outside air, the lower the temperature in the water tank 14 may be set to make it easier to cool the warmed cooling water.

[0038] [Configuration of the second flow path] The second flow path is a flow path for cooling the cooling water whose temperature has increased by absorbing heat of the cooling liquid. The second flow path branches off from the first flow path. As shown in FIG. 1, the second flow path branches off, for example, from a position between the CDU 13 and the first valve 11 in the first flow path and a position between the first valve 11 and the water tank 14 in the first flow path. The second flow path is provided with a second valve 211, a third valve 212, a second pump 22, and a cooling device 23. The second valve 211, the third valve 212, the second pump 22, and the cooling device 23 are capable of transmitting and receiving data to and from the control device 3.

[0039] The second valve 211 is a valve for controlling the flow rate of the cooling water flowing from the first flow path to the second flow path. The second valve 211 may be of either the ON-OFF control type or the continuous control type described above. When the control type is the ON-OFF control type, the second valve 211 is a valve for switching between a state in which the cooling water flows from the first flow path to the second flow path and a state in which the cooling water does not flow.

[0040] The third valve 212 is a valve for controlling the flow rate of the cooling water flowing from the second flow path to the first flow path. The third valve 212 may be either of the above-mentioned ON-OFF control method or continuous control method. When the control method is the ON-OFF control method, the third valve 212 is a valve for switching between a state in which the cooling water flows from the second flow path to the first flow path and a state in which the cooling water does not flow.

[0041] The second pump 22 is a pump for causing the cooling water to flow through the second flow path. The second pump 22 uses its power to discharge the cooling water cooled by the cooling device 23 (described later) from the cooling device 23, thereby causing the cooling water to flow through the second flow path.

[0042] The cooling device 23 is a device for cooling a part of the cooling water. The cooling water that flows into the cooling device 23 is cooled by the cooling device 23, and is discharged from the cooling device 23 by the power of the second pump 22. The cooling device 23 is, for example, a cooling tower, and is provided in a well-ventilated place (for example, a rooftop).

[0043] [Configuration of control device 3] 2 is a diagram showing an example of the configuration of the control device 3. The control device 3 includes a communication unit 31, a storage unit 32, and a control unit 33.

[0044] The communication unit 31 is a communication interface for transmitting and receiving data to and from various facilities. The communication unit 31 transmits an operation control signal input from the control unit 33 for controlling the operation amount of the pump to the first pump 12 or the second pump 22. The communication unit 31 also transmits a state control signal input from the control unit 33 for controlling the state of the valve to the first valve 11, the second valve 211, or the third valve 212.

[0045] The communication unit 31 receives power consumption data indicating the power consumption of the pump from the first pump 12 or the second pump 22. The communication unit 31 receives status data indicating the status of the valve from the first valve 11, the second valve 211, or the third valve 212. The communication unit 31 receives temperature data indicating the temperature of the cooling water flowing through the first flow path from a thermometer installed in the first flow path. The communication unit 31 receives temperature data from a thermometer installed, for example, downstream of the CDU 13 in the first flow path (after heat exchange), inside the tank (inside the water tank) of the water tank 14, and / or a location in the water tank 14 where the cooling water flows in (water tank inlet). The communication unit 31 notifies the control unit 33 of the received power consumption data, status data, and temperature data.

[0046] The storage unit 32 is a storage medium including a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The storage unit 32 stores a program executed by the control unit 33. The storage unit 32 stores a state management table and a power record table.

[0047] 3 is a diagram showing an example of the state management table. The state management table is a table used by the control unit 33 to control the states of the pump and the valves according to the temperature of the cooling water flowing in the first flow path. In the state management table, the temperature of the cooling water flowing in the first flow path, the operating state of the pump, and the state of the valve are associated with each other.

[0048] 3, the operation state of the pump is either "operated" or "not operated", but the higher the temperature of the cooling water flowing through the first flow path, the greater the operation amount of the second pump 22 may be set to improve cooling efficiency. Also, in the example of the state management table shown in FIG 3, the state of the valve is either "open" or "closed", but the higher the temperature of the cooling water flowing through the first flow path, the greater the valve opening of the second valve 211 or the third valve 212 may be set to improve cooling efficiency.

[0049] FIG. 4 is a diagram showing an example of a power record table. The power record table is a table to be learned by a machine learning model used by the control device 3 to predict the minimum power value of the pump. In the power record table, the data acquisition date and time, the temperature of the cooling water, the open / close state of the valve, and the power consumption of the pump are associated with each other. The power consumption of the pump is, for example, the power consumption of the pump from one hour before the data acquisition date and time to the data acquisition date and time. In the power record table shown in FIG. 3, the temperature after the above-mentioned heat exchange, the temperature in the water tank, and the temperature at the inlet of the water tank are recorded as the temperature of the cooling water, but at least one of these temperatures may be recorded, or an average value of these may be recorded.

[0050] The control unit 33 is, for example, a CPU (Central Processing Unit). The control unit 33 executes an information processing program stored in the storage unit 32.

[0051] The control unit 33 acquires the temperature of the cooling water flowing in the first flow path. For example, the control unit 33 acquires, as the temperature of the cooling water flowing in the first flow path, any one of the three cooling water temperatures received by the communication unit 31, the cooling water temperature after heat exchange, the cooling water temperature in the water tank, and the cooling water temperature at the inlet of the water tank. The control unit 33 may acquire, as the temperature of the cooling water flowing in the first flow path, the average value of the three cooling water temperatures.

[0052] The control unit 33 controls the flow rate (first flow rate) of the cooling water circulating in the first flow path without flowing from the first flow path to the second flow path and the flow rate (second flow rate) of the cooling water flowing from the first flow path into the second flow path, cooled by the cooling device 23, and then returning to the first flow path, according to the temperature of the cooling water flowing in the first flow path. For example, when the temperature of the cooling water flowing in the first flow path is less than a first threshold, the control unit 33 controls the flow rate of the cooling water so that the second flow rate is less than the first flow rate. On the other hand, for example, when the temperature of the cooling water flowing in the first flow path is equal to or higher than the first threshold, the control unit 33 controls the flow rate of the cooling water so that the second flow rate is greater than the second flow rate when the temperature of the cooling water flowing in the first flow path is less than the first threshold.

[0053] When the temperature of the cooling water flowing through the first flow path is less than a first threshold, the control unit 33 may relatively reduce the operation amount of the second pump 22. For example, when the temperature of the cooling water flowing through the first flow path is less than the first threshold, the control unit 33 transmits, via the communication unit 31, an operation control signal indicating a first operation amount to the first pump 12, and transmits an operation control signal indicating a second operation amount smaller than the first operation amount to the second pump 22.

[0054] On the other hand, the control unit 33 may relatively increase the operation amount of the second pump 22 when the temperature of the cooling water flowing through the first flow path is equal to or higher than the first threshold. For example, when the temperature of the cooling water flowing through the first flow path is equal to or higher than the first threshold, the control unit 33 transmits to the second pump 22 an operation control signal indicating a cooling operation amount larger than the second operation amount. The higher the temperature of the cooling water flowing through the first flow path, the greater the operation amount for cooling may be transmitted to the second pump 22 in order to perform cooling more efficiently. Furthermore, since the cooling water is more easily warmed by the outside air as the temperature of the outside air is higher, the control unit 33 may transmit to the second pump 22 an operation control signal indicating a cooling operation amount larger as the temperature of the outside air is higher in order to perform cooling more efficiently.

[0055] The control unit 33 may control the flow rate of the cooling water by controlling the states of the first valve 11, the second valve 211, and the third valve 212. When the temperature of the cooling water flowing in the first flow path is lower than a first threshold, for example, the valve opening indicated by the state control signal transmitted by the control unit 33 to the first valve 11 is larger than the valve opening indicated by the state control signal transmitted by the control unit 33 to the second valve 211 and the third valve 212. On the other hand, when the temperature of the cooling water flowing in the first flow path is equal to or higher than the first threshold, for example, the valve opening indicated by the state control signal transmitted by the control unit 33 to the second valve 211 and the third valve 212 is larger than the valve opening indicated by the state control signal transmitted by the control unit 33 to the first valve 11. The control unit 33 may transmit state control signals indicating larger valve openings to the second valve 211 and the third valve 212 in order to perform cooling more efficiently as the temperature of the cooling water flowing in the first flow path is higher.

[0056] In this way, when the temperature of the cooling water flowing through the first flow path is less than the first threshold and cooling is not required, the control unit 33 controls the flow rate of the cooling water so that the second flow rate through the second flow path for cooling is less than the first flow rate, thereby reducing the power required to flow the cooling water through the second flow path. As a result, the power consumption required for cooling the server device SV can be reduced.

[0057] So far, an example has been described in which the control unit 33 controls the flow rate of the cooling water flowing from the first flow path to the second flow path depending on whether the temperature of the cooling water flowing in the first flow path is less than the first threshold value. In contrast, as described below, when the temperature of the cooling water flowing in the first flow path is less than the first threshold value, the control unit 33 may control the flow rate of the cooling water by controlling the flow of the cooling water so that the cooling water does not flow from the first flow path to the second flow path but circulates in the first flow path. On the other hand, when the temperature of the cooling water flowing in the first flow path is equal to or higher than the first threshold value, the control unit 33 may control the flow rate of the cooling water by controlling the flow of the cooling water so that the cooling water flows from the first flow path to the second flow path and the cooling water that has flowed into the second flow path is cooled by the cooling device 23 and then returns to the first flow path.

[0058] When the temperature of the cooling water flowing through the first flow path is less than a first threshold value, the control unit 33 may not operate the second pump 22 or may reduce the operation amount of the second pump 22. When the temperature of the cooling water flowing through the first flow path is less than the first threshold value, for example, the control unit 33 refers to the state management table (FIG. 3) and acquires an operation control signal indicating "to operate" the first pump 12 and an operation control signal indicating "not to operate" the second pump 22. The control unit 33 transmits the acquired operation control signals to the first pump 12 and the second pump 22 via the communication unit 31, for example.

[0059] On the other hand, when the temperature of the cooling water flowing through the first flow path is equal to or higher than the first threshold, the control unit 33 may operate the second pump 22 or may increase the operation amount of the second pump 22. For example, when the temperature of the cooling water flowing through the first flow path is equal to or higher than the first threshold, the control unit 33 refers to the state management table ( FIG. 3 ) and acquires an operation control signal that indicates to "operate" the first pump 12 and the second pump 22. For example, the control unit 33 transmits the acquired operation control signal to the first pump 12 and the second pump 22 via the communication unit 31.

[0060] The control unit 33 may control the opening and closing states of the first valve 11, the second valve 211, and the third valve 212 so that the first valve 11 is in an open state and the second valve 211 and the third valve 212 are in a closed state when the temperature of the cooling water flowing through the first flow path is less than a first threshold value. For example, when the temperature of the cooling water flowing through the first flow path is less than a first threshold value, the control unit 33 refers to the state management table (FIG. 3) and acquires a state control signal indicating "open" for the first valve 11 and acquires a state control signal indicating "close" for the second valve 211 and the third valve 212. The control unit 33 transmits the acquired state control signals to the first valve 11, the second valve 211, and the third valve 212 via the communication unit 31, for example.

[0061] On the other hand, the control unit 33 may control the opening and closing states of the first valve 11, the second valve 211, and the third valve 212 so that the first valve 11 is closed and the second valve 211 and the third valve 212 are open when the temperature of the cooling water flowing through the first flow path is equal to or higher than the first threshold. For example, when the temperature of the cooling water flowing through the first flow path is equal to or higher than the first threshold, the control unit 33 refers to the state management table (FIG. 3) and acquires a state control signal indicating "close" for the first valve 11 and acquires a state control signal indicating "open" for the second valve 211 and the third valve 212. The control unit 33 transmits the acquired state control signals to the first valve 11, the second valve 211, and the third valve 212 via the communication unit 31, for example.

[0062] Incidentally, in order to efficiently cool the server device SV, it is desirable to efficiently perform heat exchange in the CDU 13 as a heat exchanger. When the difference between the temperature of the cooling water flowing into the CDU 13 and the temperature of the cooling water flowing out from the CDU 13 is small, the heat exchange in the CDU 13 may be insufficient. Therefore, in order to improve the efficiency of heat exchange in the CDU 13, the control unit 33 may control the operation of the first pump 12 based on the temperature difference between the temperature of the cooling water flowing into the CDU 13 and the temperature of the cooling water flowing out from the CDU 13, thereby controlling the flow rate of the cooling water flowing in the first flow path.

[0063] For example, when the temperature difference between the temperature of the cooling water flowing into the CDU 13 and the temperature of the cooling water flowing out from the CDU 13 is less than a second threshold value (for example, 5°C), the control unit 33 controls the operation of the first pump 12 so that the flow rate of the cooling water flowing through the first flow path is reduced. The control unit 33 may control the operation of the first pump 12 so that the flow rate of the cooling water is reduced as the temperature difference is smaller.

[0064] In this way, when the temperature difference of the cooling water before and after flowing into the CDU 13 is small, the control unit 33 reduces the flow rate of the cooling water, thereby lengthening the time for the cooling water to pass through the CDU 13. As a result, heat exchange between the cooling liquid and the cooling water is easily performed in the CDU 13, and the efficiency of heat exchange is improved, so that the server device SV can be efficiently cooled.

[0065] On the other hand, when the temperature difference of the cooling water before and after flowing into the CDU 13 is large, it is considered that the heat exchange is sufficient, but the flow rate of the cooling water flowing through the first flow path may be too low. If the flow rate is too low, dirt or the like may adhere to the inner surface of the pipe through which the cooling water flows, and the pipe may corrode or become clogged. Therefore, when the temperature difference between the temperature of the cooling water flowing into the CDU 13 and the temperature of the cooling water flowing out from the CDU 13 is equal to or greater than a third threshold value (e.g., 10°C) that is greater than the second threshold value, the control unit 33 may control the operation of the first pump 12 so that the flow rate of the cooling water flowing through the first flow path increases. For example, the control unit 33 controls the operation of the first pump 12 so that the flow rate of the cooling water increases as the temperature difference increases.

[0066] In this way, when the control unit 33 increases the flow rate of the cooling water when there is a large temperature difference between the cooling water before and after it flows into the CDU 13, dirt and the like are less likely to adhere to the inner surface of the pipe through which the cooling water flows. As a result, the condition of the pipe can be kept good and the flow of the cooling water can be kept normal.

[0067] In this manner, the heat exchange function of the CDU 13 can be maintained at an appropriate level, but in order to suppress the power consumption associated with cooling the server device SV, it is important to minimize the amount of operation of the pump that controls the flow rate of the cooling water flowing through the flow path. Therefore, the control unit 33 may control the flow rate of the cooling water flowing through the flow path based on the temperature of the cooling water flowing through the flow path. For example, the control unit 33 controls the operation of the pump at the minimum power value required to set the flow rate of the cooling water to a value that allows the temperature of the cooling water after heat exchange between the cooling water and the cooling liquid to fall within a predetermined range.

[0068] The control unit 33, for example, refers to the power record table (FIG. 4) to acquire a first consumption amount, which is the power consumption amount of the pump associated with the temperature of the cooling water after heat exchange that is closest to the lower limit value of the specified predetermined range. The control unit 33 also, for example, refers to the power record table (FIG. 4) to acquire a second consumption amount, which is the power consumption amount of the pump associated with the temperature of the cooling water after heat exchange that is closest to the upper limit value of the specified predetermined range. The control unit 33 then determines, for example, the intermediate value between the acquired first and second consumption amounts as a minimum power value, and controls the operation of the pump at the determined minimum power value.

[0069] The control unit 33 may use a machine learning model to determine the minimum power value with higher accuracy. The machine learning model is a machine learning model trained by machine learning using, for example, the temperature of the coolant after the coolant exchanges heat with the coolant and the power consumption of the pump required to bring the coolant to that temperature as training data. Specifically, the machine learning model is a machine learning model trained by machine learning using a power record table (FIG. 4) as training data.

[0070] The control unit 33 may determine the minimum power value based on the predicted required power value for the pump output by the machine learning model by inputting a predetermined range of the cooling water temperature to the machine learning model. The control unit 33 may determine the predicted required power value output by the machine learning model itself as the minimum power value, or may determine the minimum power value to be a value obtained by multiplying the predicted required power value output by the machine learning model by a coefficient indicating an environmental factor such as the outside air temperature or the deterioration degree of the piping.

[0071] In this manner, the control unit 33 performs optimal control to control the operation of the pump at the minimum power value that allows the temperature of the cooling water after heat exchange to be within an acceptable range, thereby minimizing the power consumption associated with cooling the server device SV.

[0072] There are cases where it is desired to objectively evaluate the effect of reducing power consumption by the cooling system S described above. In this regard, the control unit 33 may specify normal power, which is power consumption when the flow of the cooling water is controlled so that the cooling water that has flowed into the second flow path returns to the first flow path after being cooled by the cooling device 23 for a predetermined period of time. The normal power can also be said to be power required by a conventional cooling system that controls the flow of the cooling water so that the cooling water flows into the cooling device regardless of the temperature of the cooling water.

[0073] On the other hand, the control unit 33 may specify the circulation power, which is the power consumption when the time during which the flow of the cooling water is controlled so that the cooling water circulates in the first flow path without flowing from the first flow path to the second flow path is a predetermined time. For example, the control unit 33 may specify the normal power and the circulation power when the time during which the flow of the cooling water is controlled in a state in which the temperature of the cooling water after heat exchange by the CDU 13 is within a predetermined range is a predetermined time.

[0074] The control unit 33 calculates the power reduction achieved by circulating the cooling water in the first flow path by subtracting the circulation power from the normal power, and outputs the calculated power reduction. This allows a manager or the like who manages the cooling system S to know how much power reduction has been achieved by controlling the flow of the cooling water so that the cooling water circulates in the first flow path when the temperature of the cooling water is below the first threshold value.

[0075] [Flow of processing executed by the control device 3] 5 is a flowchart showing the flow of processing executed by the control device 3. The control unit 33 periodically (for example, once an hour) acquires the temperature of the cooling water circulating in the first flow path without flowing into the second flow path (S1).

[0076] The control unit 33 determines whether the acquired temperature of the cooling water is equal to or higher than the first threshold (S2). When the control unit 33 determines that the acquired temperature of the cooling water is not equal to or higher than the first threshold (S2: NO), the control unit 33 continues to control the flow of the cooling water so that the second flow rate is smaller than the first flow rate. Then, the process returns to S1, and the control unit 33 again acquires the temperature of the cooling water circulating in the first flow path.

[0077] On the other hand, when the control unit 33 determines that the acquired temperature of the cooling water is equal to or higher than the first threshold (S2: YES), the control unit 33 opens the second flow path more than in the current state, thereby controlling the flow of the cooling water so that the second flow rate is greater than the second flow rate when the temperature of the cooling water flowing through the first flow path is less than the first threshold (S3). The control unit 33 acquires the temperature of the cooling water circulating through the first flow path after a first predetermined time has elapsed since the second flow path was opened (S4). The first predetermined time is, for example, a time considered to be necessary to return the cooling water, which has reached a temperature equal to or higher than the first threshold, to a temperature below the first threshold.

[0078] The control unit 33 determines whether the acquired cooling water temperature is below the first threshold value (S5). When the control unit 33 determines that the acquired cooling water temperature is not below the first threshold value (S5: NO), the control unit 33 acquires the temperature of the cooling water circulating in the first flow path again after a second predetermined time has elapsed. The second predetermined time is a time for additional cooling when cooling is insufficient, and is therefore, for example, shorter than the first predetermined time.

[0079] On the other hand, if the control unit 33 determines that the acquired cooling water temperature has become less than the first threshold value (S5: YES), it controls the flow of cooling water so that the second flow rate is less than the first flow rate by closing the second flow path more than in the current state (S6).

[0080] The control unit 33 determines whether or not an end signal for ending the process has been input (S7). The end signal is a signal that is input when the cooling system S is temporarily stopped for maintenance of a pump, a valve, or a pipe in the cooling system S, for example.

[0081] When the control unit 33 determines that the end signal has not been input (S7: NO), the control unit 33 returns to S1 and acquires again the temperature of the cooling water circulating in the first flow path. On the other hand, when the control unit 33 determines that the end signal has been input (S7: YES), the control unit 33 ends the process.

[0082] 6 is a flowchart showing a process flow for opening the second flow path by the continuous control method.The control unit 33 acquires the temperature of the cooling water circulating in the first flow path (S31).

[0083] The control unit 33 determines the temperature difference between the target temperature of the cooling water circulating in the first flow path stored in the memory unit 32 and the actual temperature of the cooling water acquired in S31, and inputs the determined temperature difference to a PID (Proportional-Integral-Derivative) controller (S32). The PID controller may be provided in the control device 3 or may be a controller external to the control device 3.

[0084] The control unit 33 determines the opening degree of each valve based on the calculation result by the PID controller (S33). The control unit 33 transmits a state control signal indicating the opening degree of each valve determined in S33 to each valve (S34). As a result, each valve opens at the opening degree indicated by the state control signal.

[0085] [Effects of Cooling System S] As described above, the cooling system S controls, depending on the temperature of the cooling water flowing through the first flow path, the flow rate of the cooling water circulating through the first flow path without flowing from the first flow path to the second flow path, and the flow rate of the cooling water flowing from the first flow path to the second flow path and returning to the first flow path after being cooled by the cooling device 23. As a result, it is possible to reduce the power required to flow the cooling water through the second flow path, and therefore the power consumption associated with cooling the server device SV.

[0086] <Modification> In the above-described embodiment, an example has been described in which the cooling water is cooled by the cooling device 23. In a modified example, the cooling water may be pre-cooled using external water before being cooled by the cooling device 23.

[0087] 7 is a diagram showing an outline of the operation of the cooling system S in a modified example. In the modified example, external water (e.g., river water, irrigation water, reservoir water, well water, etc.) present outside the first and second flow paths is pumped up by the power of an external pump 41 and flows into the primary side of a heat exchanger HEX (Heat Exchanger) 24, which is a heat exchanger. The external water that flows out of the primary side of HEX 24 is returned to the location where the external water is present. Meanwhile, the cooling water that flows into the second flow path from the first flow path due to an increase in temperature flows into the secondary side of HEX 24.

[0088] The heat of the cooling water that has flowed into the secondary side of the HEX 24 and has increased in temperature is transferred to the external water that has flowed into the primary side of the HEX 24. In this way, heat is exchanged between the cooling water and the external water, and the cooling water flows into the cooling device 23 with its temperature lowered to a certain degree. Therefore, in the modified example, compared to the above-mentioned embodiment in which external water is not used, the time until the temperature of the cooling water returns to less than the first threshold is shorter, and the time for operating the second pump 22 for cooling the cooling water whose temperature has reached the first threshold or higher is also shorter. As a result, less power is required to operate the second pump 22, and the power consumption associated with cooling the server device SV can be further reduced.

[0089] The heat transferred from the cooling water to the external water may be further transferred to water that needs to be heated (such as low-temperature hot spring water), thereby making effective use of the heat transferred to the external water.

[0090] In addition, if the water quality of the second flow path cannot be guaranteed or if the temperature of the cooling water in the second flow path is extremely low and condensation in the first flow path is expected, a heat exchanger may be provided to separate the first flow path from the second flow path.

[0091] Furthermore, this invention will make it possible to contribute to Goal 9 of the United Nations' Sustainable Development Goals (SDGs), which is to "build resilient infrastructure, promote industry, innovation and infrastructure."

[0092] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination combines the effect of the original embodiment. [Explanation of symbols]

[0093] 11 First valve 12 First Pump 13 CDU 14 Water tank 211 Second valve 212 3rd valve 22 Second Pump 23 Cooling device 24 HEX 3. Control device 31 Communications Department 32 Storage section 33 Control Unit 41 External Pump S Cooling System SV server device

Claims

1. a first flow path through which cooling water circulates to cool a cooling liquid for cooling a server device by exchanging heat with the cooling liquid; a second flow path branched from the first flow path and provided with a cooling device for cooling a portion of the cooling water; a control device that controls, in accordance with a temperature of the cooling water flowing through the first flow path, a flow rate of the cooling water circulating through the first flow path without flowing from the first flow path to the second flow path, and a flow rate of the cooling water flowing from the first flow path into the second flow path, being cooled by the cooling device, and then returning to the first flow path; A cooling system having

2. The control device includes: When a temperature of the cooling water flowing through the first flow path is less than a first threshold value, the flow rate of the cooling water is controlled by controlling the flow of the cooling water such that the cooling water circulates through the first flow path without flowing from the first flow path to the second flow path, and when a temperature of the cooling water flowing through the first flow path is equal to or greater than the first threshold value, the flow rate of the cooling water is controlled by controlling the flow of the cooling water such that the cooling water flows from the first flow path to the second flow path, and the cooling water that has flowed into the second flow path is cooled by the cooling device and then returns to the first flow path. The cooling system of claim 1 .

3. a second pump is provided in the second flow path to cause the cooling water to flow through the second flow path, the control device relatively reduces an operating amount of the second pump when a temperature of the cooling water flowing through the first flow path is lower than a first threshold, and relatively increases an operating amount of the second pump when a temperature of the cooling water flowing through the first flow path is equal to or higher than the first threshold. The cooling system of claim 1 .

4. a first valve for controlling a flow rate of the cooling water circulating in the first flow path is provided in the first flow path, the second flow path is provided with a second valve for controlling a flow rate of the cooling water flowing from the first flow path to the second flow path, and a third valve for controlling a flow rate of the cooling water flowing from the second flow path to the first flow path, The control device controls the flow rate of the cooling water by controlling states of the first valve, the second valve, and the third valve. The cooling system of claim 1 .

5. the control device controls opening and closing states of the first valve, the second valve, and the third valve so that the first valve is in an open state and the second valve and the third valve are in a closed state when the temperature of the cooling water flowing through the first flow path is less than a first threshold value, and controls opening and closing states of the first valve, the second valve, and the third valve so that the first valve is in a closed state and the second valve and the third valve are in an open state when the temperature of the cooling water flowing through the first flow path is equal to or higher than the first threshold value. The cooling system of claim 4.

6. The first flow path is provided with a first pump for causing the cooling water to flow through the first flow path, and a heat exchanger for exchanging heat between the cooling liquid and the cooling water, The control device controls the flow rate of the cooling water flowing through the first flow path by controlling the operation of the first pump based on a temperature difference between the temperature of the cooling water flowing into the heat exchanger and the temperature of the cooling water flowing out of the heat exchanger. The cooling system of claim 1 .

7. When the temperature difference is less than a second threshold value, the control device controls the operation of the first pump so that a flow velocity of the cooling water flowing through the first flow path is reduced. The cooling system of claim 6.

8. the control device controls the operation of the first pump so that a flow velocity of the cooling water flowing through the first flow path increases when the temperature difference is equal to or greater than a third threshold value that is greater than the second threshold value.

8. A cooling system according to claim 6 or 7.

9. The control device controls a flow rate of the cooling water flowing through the flow path based on a temperature of the cooling water flowing through the flow path. The cooling system of claim 1 .

10. At least one of the first flow path and the second flow path is provided with a pump that controls a flow rate of the cooling water flowing through the flow path, the control device controls the operation of the pump at a minimum power value required to make the flow rate of the cooling water such that the temperature of the cooling water after heat exchange between the cooling water and the cooling liquid can be within a predetermined range. The cooling system of claim 9.

11. the control device determines the minimum power value based on an expected power required by the pump outputted from a machine learning model that is trained by machine learning using training data of the temperature of the cooling water after the cooling water has exchanged heat with the cooling liquid and the power consumption of the pump required to bring the temperature of the cooling water to the temperature; and The cooling system of claim 10.

12. The control device calculates the reduced power due to the circulation by subtracting the power consumption when the time during which the flow of the cooling water is controlled so that the cooling water that has flowed into the second flow path is returned to the first flow path after being cooled by the cooling device is the predetermined time, from the power consumption when the time during which the flow of the cooling water is controlled so that the cooling water does not flow from the first flow path to the second flow path and circulates within the first flow path, and outputs the calculated reduced power. The cooling system of claim 1 .

13. The first flow path is provided with a water tank for storing the cooling water in an amount larger than the capacity of the first flow path. The cooling system of claim 1 .

14. The computer executes a step of controlling a flow rate of the cooling water circulating in a first flow path, the cooling water circulating in the first flow path and cooling the cooling water by heat exchange with a cooling liquid for cooling a server device, without flowing from the first flow path into a second flow path provided with a cooling device for cooling a part of the cooling water, and a flow rate of the cooling water flowing from the first flow path into the second flow path, being cooled by the cooling device, and then returning to the first flow path, according to a temperature of the cooling water flowing in the first flow path through which the cooling water circulates and which cools the cooling water by heat exchange with the cooling liquid for cooling the server device. Cooling method.

15. a flow rate of the cooling water circulating in a first flow path, the cooling water circulating in the first flow path and cooling the cooling water by heat exchange with a cooling liquid for cooling a server device, without flowing from the first flow path into a second flow path provided with a cooling device for cooling a part of the cooling water, and a flow rate of the cooling water flowing from the first flow path into the second flow path, being cooled by the cooling device, and then returning to the first flow path, are controlled according to a temperature of the cooling water flowing in the first flow path through which the cooling water circulates and which cools the cooling water by heat exchange with a cooling liquid for cooling a server device. Control device.

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