Coolant Circulation Unit and Control Method and Program Thereof

Abstract

To set a cooling condition with the amount of heat generated by electronic equipment taken into consideration.SOLUTION: A cooling liquid circulation unit circulates cooling liquid with respect to a liquid immersion bath in which a plurality of electronic equipment is immersed in cooling liquid and cooled. The cooling circulation unit comprises: a flow volume adjustment unit arranged in a cooling liquid circulation path for circulating the cooling liquid with respect to the liquid immersion bath; a heat exchanger arranged in the cooling liquid circulation path and exchanging heat between the coolant and a cooling medium; and a cooling circulation unit control unit 70a. The cooling circulation unit control unit 70a comprises: a mode selection unit 51 that selects one of a plurality of cooling modes; a calculation unit 52 that calculates the required cooling amount on the basis of parameters relating to the operating states of the plurality of electronic equipment; and a cooling condition setting unit 53b that sets target values of parameters relating to the flow volume of the coolant on the basis of the selected cooling mode and the required cooling amount.SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] The present disclosure relates to a coolant circulation unit that circulates a coolant through an immersion bath, and a control method and program thereof. [Background technology]

[0002] Patent Document 1 discloses an immersion cooling system in which electronic devices such as servers and storage devices are immersed in a cooling liquid in a data center to cool them. Specifically, Patent Document 1 discloses an immersion cooling system in which the cooling liquid that has been heated by cooling electronic devices in a cooling tank is cooled in a heat exchanger and the cooled cooling liquid is returned to the cooling tank, thereby circulating the cooling liquid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6658312 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, the amount of heat generated by electronic devices is not constant but changes, so it is desirable to change the cooling conditions according to the amount of heat generated.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a coolant circulation unit and a control method and program thereof that can set cooling conditions taking into account the amount of heat generated by electronic devices. [Means for solving the problem]

[0006] A first aspect of the present disclosure is a coolant circulation unit that circulates a coolant through an immersion bath in which a plurality of electronic devices are immersed in the coolant to cool them, the unit including a flow rate adjustment unit provided in a coolant circulation path that circulates the coolant through the immersion bath, a heat exchanger provided in the coolant circulation path and performing heat exchange between the coolant and a cooling medium, and a coolant circulation unit controller, the coolant circulation unit controller including a mode selection unit that selects one of a plurality of cooling modes, a calculation unit that calculates a required amount of cooling based on parameters related to operating states of the plurality of electronic devices, and a cooling condition setting unit that sets a target value of a parameter related to the flow rate of the coolant based on the selected cooling mode and the required amount of cooling. the plurality of cooling modes include an energy saving priority mode that prioritizes power usage efficiency, and when the energy saving priority mode is selected, the cooling condition setting unit sets a temperature at which the cooling liquid is sent to the immersion bath based on a predetermined temperature that is determined based on heat resistance characteristics of electronic components that constitute the electronic device, and sets a target flow rate of the cooling liquid to a minimum flow rate of the cooling liquid that satisfies the required cooling amount. It is a cooling liquid circulation unit. A second aspect of the present disclosure is a coolant circulation unit that circulates a coolant through an immersion tank in which a plurality of electronic devices are immersed in the coolant to cool them, the coolant circulation unit comprising: a flow rate adjustment unit provided in a coolant circulation path that circulates the coolant through the immersion tank; a heat exchanger provided in the coolant circulation path and performing heat exchange between the coolant and a cooling medium; and a coolant circulation unit control unit, the coolant circulation unit control unit comprising: a mode selection unit that selects one of a plurality of cooling modes; a calculation unit that calculates a required amount of cooling based on parameters related to the operating states of the plurality of electronic devices; a correction unit that corrects the required amount of cooling based on a deviation between a distribution of parameters indicating the operating states of the plurality of electronic devices for the arrangement of the plurality of electronic devices in the immersion tank and a cooling efficiency distribution in the immersion tank; and a cooling condition setting unit that sets a target value of a parameter related to the flow rate of the coolant based on the selected cooling mode and the corrected required amount of cooling.

[0007] The present disclosure 3 The aspect is a control method for a coolant circulation unit that circulates a coolant through an immersion bath that cools a plurality of electronic devices by immersing them in the coolant, the coolant circulation unit including a flow rate regulator provided in a coolant circulation path that circulates the coolant through the immersion bath, and a heat exchanger provided in the coolant circulation path that exchanges heat between the coolant and a cooling medium, the control method including selecting any one of a plurality of cooling modes Mode Selection and calculating a required amount of cooling based on parameters related to the operating states of the electronic devices. calculation and setting a target value of a parameter related to the flow rate of the cooling liquid based on the selected cooling mode and the required cooling amount. Cooling condition setting Process and the plurality of cooling modes include an energy saving priority mode that prioritizes power usage efficiency, and the cooling condition setting step, when the energy saving priority mode is selected, sets a temperature at which the cooling liquid is sent to the immersion bath based on a predetermined temperature that is determined based on heat resistance characteristics of electronic components that constitute the electronic device, and sets a target flow rate of the cooling liquid to a minimum flow rate of the cooling liquid that satisfies the required cooling amount. The present invention relates to a method for controlling a cooling liquid circulation unit. A fourth aspect of the present disclosure is a control method for a coolant circulation unit that circulates a coolant through an immersion bath in which a plurality of electronic devices are immersed in the coolant to cool them, the coolant circulation unit comprising a flow rate adjuster provided in a coolant circulation path that circulates the coolant through the immersion bath, and a heat exchanger provided in the coolant circulation path and performing heat exchange between the coolant and a cooling medium, the control method including a mode selection step of selecting one of a plurality of cooling modes, a calculation step of calculating a required cooling amount based on parameters related to the operating states of the plurality of electronic devices, a correction step of correcting the required cooling amount based on a deviation between a distribution of parameters indicating the operating states of the plurality of electronic devices for the arrangement of the plurality of electronic devices in the immersion bath and a cooling efficiency distribution in the immersion bath, and a cooling condition setting step of setting a target value of a parameter related to the flow rate of the coolant based on the selected cooling mode and the corrected required cooling amount.

[0008] The present disclosure 5 One aspect is a program for causing a computer to function as the coolant circulation unit control unit.

[0009] The present disclosure 6One aspect is an immersion cooling system including the above-described cooling liquid circulation unit and the immersion tank. Effect of the Invention

[0010] The cooling conditions can be set taking into consideration the amount of heat generated by the electronic device. [Brief description of the drawings]

[0011] [Figure 1] 1 is a system configuration diagram showing a schematic system configuration of an immersion cooling system according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a perspective view showing a specific example of the inside of the immersion tank in FIG. [Diagram 3] 3 is a perspective view showing the flow of a cooling liquid for each substrate in FIG. 2. [Figure 4] 2 is a diagram illustrating an example of a hardware configuration of a system control device according to the first embodiment of the present disclosure. FIG. [Diagram 5] 2 is a functional block diagram showing an example of functions provided in the system control device according to the first embodiment of the present disclosure. FIG. [Figure 6] 4 is a flowchart showing an example of a procedure of a control method for a coolant circulation system implemented by the system control device according to the first embodiment of the present disclosure. [Figure 7] 4 is a flowchart showing an example of a procedure of a control method for a coolant circulation system implemented by the system control device according to the first embodiment of the present disclosure. [Figure 8] FIG. 11 is a functional block diagram showing an example of functions provided in a system control device according to a second embodiment of the present disclosure. [Figure 9] 13 is a diagram for explaining a deviation between a power consumption amount distribution and a cooling efficiency distribution in a system control device according to a second embodiment of the present disclosure. FIG. [Figure 10] FIG. 13 is a diagram showing an example of a change over time in a calculation job given to each board (first board to fifth board). [Figure 11] FIG. 11 is a perspective view showing the flow of cooling liquid for each substrate in an immersion cooling system according to a third embodiment of the present disclosure. [Figure 12] FIG. 11 is a functional block diagram showing an example of functions provided in a system control device according to a third embodiment of the present disclosure. [Figure 13] FIG. 13 is a functional block diagram showing an example of functions of a cooling unit control unit according to a fourth embodiment of the present disclosure. [Figure 14] FIG. 13 is a functional block diagram showing an example of functions of a coolant circulation unit control unit according to a fifth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a number of embodiments according to the present disclosure will be described with reference to the drawings. [First embodiment] The first embodiment of the present disclosure will be described below. 1 is a schematic diagram showing a schematic configuration of an immersion cooling system 1 according to this embodiment. The immersion cooling system 1 includes an immersion tank (container) 3 and a cooling liquid circulation system 6.

[0013] The immersion tank 3 is a bottomed container in which the cooling liquid Lq is stored. The immersion tank 3 has a bottomed main body 3a having side walls 3b on all four sides, and an openable / closable lid 3c provided on the top surface of the main body 3a. The coolant Lq is an electrically insulating liquid, such as silicone oil, etc. The coolant Lq is filled to a height sufficient to completely immerse the substrate 11 placed in the main body 3a of the immersion tank 3.

[0014] The opening / closing lid 3c opens and closes by rotating around the upper end of the side wall portion 3b. The opening / closing lid 3c is opened when the substrate 11 is placed in or removed from the main body 3a of the immersion tank 3, or during maintenance of the inside of the immersion tank 3. The opening / closing lid 3c is closed during normal use (when the substrate 11 is being cooled).

[0015] A plurality of electronic devices are immersed in the main body 3a of the immersion tank 3, for example, by being mounted on each of the substrates 11. Examples of electronic devices include electronic computers (servers) and storage devices. FIG. 1 shows, as an example, a case in which a plurality of substrates 11 are installed in the immersion tank 3. Each substrate 11 is, for example, a substrate that constitutes a server, and is arranged at a predetermined interval with its longitudinal direction facing vertically. Note that the arrangement of the substrates and the manner in which the electronic devices are mounted are not limited to this.

[0016] The coolant circulation system 6 circulates the coolant through the immersion tank 3. Specifically, the coolant circulation system 6 cools the coolant that has been heated by cooling the electronic devices mounted on the substrate 11 in the immersion tank 3 by the heat exchanger 17, and returns the cooled coolant to the immersion tank 3, thereby circulating the coolant.

[0017] The coolant circulation system 6 includes a coolant circulation unit 5, a cooling unit 7, and a system control device 40 (see FIG. 4) described below. The coolant circulation unit 5 includes a coolant circulation path, a pump 19, and a heat exchanger 17. The coolant circulation path includes, for example, a liquid return pipe 15, a coolant discharge pipe 21, and a liquid delivery pipe 13. The coolant circulation path is also provided with the pump 19 and the heat exchanger 17.

[0018] The coolant circulation unit 5 is connected to the immersion tank 3 via, for example, a liquid supply pipe 13 and a liquid return pipe 15. A downstream end 13a of the liquid supply pipe 13 is connected to a side wall 3b of the immersion tank 3. An upstream end 13b of the liquid supply pipe 13 is connected to a heat exchanger 17 installed inside the coolant circulation unit 5. An upstream end 15a of the liquid return pipe 15 is connected to the side wall 3b of the immersion tank 3. A downstream end 15b of the liquid return pipe 15 is connected to a pump (first flow rate adjustment unit) 19 installed inside the coolant circulation unit 5 for circulating the coolant.

[0019] The heat exchanger 17 exchanges heat between the cooling water supplied from the cooling unit 7 and the cooling liquid supplied from the pump 19 via a cooling liquid discharge pipe 21. The cooling liquid is cooled by exchanging heat with the cooling water in the heat exchanger 17. The pump 19 is driven by, for example, an electric motor, and the discharge amount is controlled by a system control device (see FIG. 4) described later.

[0020] The coolant circulation unit 5 is provided with temperature sensors (not shown) for detecting the temperature of the coolant flowing into the heat exchanger 17 and the outlet temperature of the coolant sent out from the heat exchanger 17. The coolant circulation unit 5 may also be provided with a flow rate sensor for detecting the flow rate of the coolant.

[0021] The cooling unit 7 includes a cooling water circulation path through which cooling water (cooling medium) circulates. The cooling water circulation path includes, for example, a cooling water supply pipe 25 and a cooling water return pipe 26. The cooling water circulation path is provided with a pump (second flow rate adjustment unit) 28 for circulating the cooling water. The pump 28 is driven by, for example, an electric motor, and the discharge amount is controlled by a system control device (see FIG. 4) described later.

[0022] The cooling unit 7 includes a fan (cooling section) 23, and outside air for cooling is taken in by the fan 23. The start / stop and rotation speed of the fan 23 are controlled by a system control device (see FIG. 4) described later. The cooling water circulating through the cooling water circulation path is cooled by exchanging heat with the outside air taken in by the fan 23.

[0023] In the cooling unit 7, the cooling water cooled by heat exchange with the outside air is supplied to the heat exchanger 17 via a cooling water supply pipe 25. After heat exchange in the heat exchanger 17, the cooling water is returned to the cooling unit 7 via a cooling water return pipe 26.

[0024] The cooling unit 7 is provided with temperature sensors (not shown) for detecting a cooling water inlet temperature, which is the temperature of the cooling water flowing into the heat exchanger 17, and a cooling water outlet temperature, which is the temperature of the cooling water returned from the heat exchanger 17. The cooling unit 7 may also be provided with a flow rate sensor for detecting the cooling water flow rate.

[0025] Fig. 2 shows a plurality of substrates 11 installed in the main body 3a of the immersion tank 3. In the example shown in Fig. 2, four substrates 11 are provided in the width direction of the substrate 11 (x direction in Fig. 2) and twelve substrates 11 are provided in the depth direction (y direction in Fig. 2). However, the number of substrates 11 provided is not limited to this. A plurality of electronic devices 30, such as a CPU, a power supply unit, a memory, a storage such as a hard disk or an SSD (Solid State Drive), and a communication unit, for configuring a server are mounted on each board 11. These electronic devices 30 generate heat during operation of the server and are cooled by the coolant Lq.

[0026] A gripping portion 11a is fixed to the upper end of each substrate 11. The gripping portion 11a is provided so as to protrude upward from the upper end of the substrate 11, and has a gate-like shape formed by bending a rod-shaped body. The substrate 11 is installed and removed by an operator grasping the gripping portion 11a.

[0027] Perforated walls 11b are provided so as to be perpendicular to the upper ends of the substrates 11. The perforated walls 11b are erected on the surface side on which the electronic devices 30 are provided. The perforated walls 11b are made of, for example, punched metal with a large number of holes formed therein. The flow rate of the cooling liquid flowing on the surface of the substrates 11 can be adjusted by appropriately setting the number and diameter of the holes in the perforated walls 11b.

[0028] Each of the substrates 11 has a side plate 11c extending in the up-down direction, for example, provided on each of both sides thereof. The side plate 11c is provided so as to stand on the front surface side on which the electronic device 30 is provided, and is provided continuously over the entire longitudinal direction (up-down direction, z direction) of the substrate 11. The side plate 11c surrounds both sides of the substrate 11, thereby guiding the flow of the cooling liquid Lq flowing on the surface of the substrate 11.

[0029] A plurality of nozzles 32 are provided below each substrate 11. The nozzles 32 discharge the cooling liquid so that the cooling liquid flows from one end (lower end) of the substrate 11 to the other end (upper end) of the substrate 11 on which the electronic device 30 is provided.

[0030] For example, a plurality of nozzles 32 are provided for each substrate 11. Specifically, a plurality of nozzles 32 are provided in parallel in a width direction (x direction) intersecting with a flow direction (z direction) of the cooling liquid from one end (lower end) of the substrate 11 toward the other end (upper end). This forms a plurality of parallel flows of the cooling liquid Lq flowing from one end (lower end) of the substrate 11 to the other end (upper end). The number of nozzles 32 may be two or more for one substrate 11, and is set appropriately according to the flow of the cooling liquid Lq and the cooling state.

[0031] Similarly, the nozzles 32 are provided in the depth direction (the y direction in FIG. 2) corresponding to each substrate 11. Therefore, the nozzles 32 are also provided between the substrates 11 arranged in the y direction.

[0032] 3, the upstream side of each nozzle 32 is connected to a main supply pipe 38 via a branch pipe 36. The upstream side of the main supply pipe 38 is connected to the downstream end 13a (see FIG. 1) of the liquid feed pipe 13. Therefore, the cooling liquid Lq guided from the liquid feed pipe 13 is distributed to each branch pipe 36 via the main supply pipe 38.

[0033] The immersion cooling system 1 having such a configuration operates, for example, as follows. The pump 19 is controlled by a system control device 40, which will be described later, to cause the coolant Lq to flow and be guided to the heat exchanger 17. In the heat exchanger 17, the coolant Lq is cooled by exchanging heat with cooling water cooled in the cooling unit 7. The coolant Lq that leaves the heat exchanger 17 is guided to the immersion tank 3 through the liquid supply pipe 13. The coolant Lq guided to the immersion tank 3 is distributed from the liquid supply pipe 13 through the main supply pipe 38 to each branch pipe 36, as shown in FIG. The coolant Lq guided to each branch pipe 36 is guided to the nozzle 32 and discharged.

[0034] The cooling liquid Lq discharged from each nozzle 32 is led to the lower end of the substrate 11, and while being guided by the side plate 11c, passes over the surface of the substrate 11 on which the electronic device 30 is provided, and proceeds toward the upper end of the substrate 11. At this time, the heat generated by the electronic device 30 is absorbed by the cooling liquid Lq, and the electronic device 30 is cooled.

[0035] Cooling liquid Lq that has been heated by cooling electronic device 30 passes through holes in perforated wall 11b provided at the upper end of substrate 11 and is discharged from above substrate 11. The cooling liquid Lq discharged from above substrate 11 joins and is mixed with the cooling liquid Lq stored in main body 3a of immersion tank 3. A portion of the cooling liquid Lq stored within the main body 3a is extracted from the liquid return pipe 15, guided via the pump 19 to the heat exchanger 17 where it is cooled, and then guided back to the immersion tank 3.

[0036] Next, the system control device 40 according to the present embodiment will be described. FIG. 4 is a diagram showing an example of a hardware configuration of the system control device 40 according to the present embodiment. As shown in FIG. 4, the system control device 40 is a so-called computer, and includes, for example, a CPU (Central Processing Unit) 41, a main memory 42, a storage unit 43, and a communication unit 45. The system control device 40 may also include, for example, an input unit 46 and a display unit 47. In this case, the input unit 46 and the display unit 47 may be connected to the communication unit 45 via a communication line, and may be configured to be capable of remote operation, for example, to realize input from a remote location. The above components are connected to each other directly or indirectly via a bus, and cooperate with each other to execute various processes.

[0037] The CPU 41 controls the entire coolant circulation system 6 using, for example, an OS (Operating System) stored in a memory unit 43 connected via a bus, and performs various processes by executing various programs stored in the memory unit 43.

[0038] The main memory 42 is composed of writable memory such as a cache memory or a RAM (Random Access Memory), and is used as a working area for reading out execution programs of the CPU 41, writing processing data by the execution programs, and the like.

[0039] The storage unit 43 is a non-transitory computer readable storage medium. Examples include a ROM (Read Only Memory), an HDD (Hard Disk Drive), and a flash memory. The storage unit 43 stores an OS for controlling the entire coolant circulation system 6, such as Windows (registered trademark), iOS (registered trademark), and Android (registered trademark). The storage unit 43 may also store a BIOS (Basic Input / Output System), for example. The storage unit 43 may also store various device drivers for operating the hardware of peripheral devices, various application software, and various data and files. The storage unit 43 may also store programs for implementing various processes and various data required for implementing various processes.

[0040] The communication unit 45 functions as an interface for connecting to a network to communicate with other devices and transmitting and receiving information. For example, the communication unit 45 communicates with other devices by wire or wirelessly. Examples of wireless communication include Bluetooth (registered trademark), Wi-Fi, and communication using a dedicated communication protocol. An example of wired communication is a wired LAN (Local Area Network).

[0041] The input unit 46 is a user interface, such as a keyboard, a mouse, a touch pad, or the like, that allows the user to give instructions to the coolant circulation system 6.

[0042] The display unit 47 is, for example, a liquid crystal display, an organic EL (Electroluminescence) display, etc. Furthermore, the display unit 47 may be a touch panel display on which a touch panel is superimposed.

[0043] Fig. 5 is a functional block diagram showing an example of functions included in the system control device 40. As shown in Fig. 5, the system control device 40 includes, for example, a mode selection unit 51, a calculation unit 52, and a cooling condition setting unit 53.

[0044] All or part of these functions are realized, for example, by a processing circuitry. For example, a series of processes for realizing the functions shown below is stored in the storage unit 43 in the form of a program (for example, a system control program), and the CPU 41 reads this program into the main memory 42 and executes information processing and arithmetic processing to realize various functions.

[0045] The program may be installed in advance in the storage unit 43, may be provided in a state stored in another computer-readable storage medium, may be distributed via wired or wireless communication means, etc. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, etc.

[0046] The mode selection unit 51 has a plurality of modes. The plurality of modes may include a performance priority mode that prioritizes the performance of the electronic device 30. The plurality of modes may also include an energy saving priority mode that prioritizes power usage efficiency. The plurality of modes may also include a normal mode.

[0047] The mode selection unit 51 selects one of a plurality of modes. For example, the mode selection unit 51 selects one of the modes according to a predetermined schedule. For example, the cooling mode to be selected is scheduled in advance based on the operation schedule of the server, and the mode selection unit 51 may select the cooling mode according to this schedule. Also, the mode selection unit 51 may select a specified cooling mode based on an input instruction from the input unit 46.

[0048] The calculation unit 52 calculates the required cooling amount based on parameters related to the operating states of the multiple electronic devices 30. Here, examples of the parameters related to the operating states of the multiple electronic devices 30 include, for example, power consumption, power consumption amount, CPU load rate, or heat generation temperature, or a combination of two or more of these.

[0049] The amount of heat generated by the electronic device 30 changes depending on the operating state of the electronic device 30. Therefore, by using parameters related to the operating state of the electronic device 30, the amount of heat generated by the electronic device 30 can be estimated, and thus the amount of cooling required can be estimated. Furthermore, when acquiring the CPU load rate, communication occurs between the electronic device 30 and the system control device 40, which places a heavy burden on the electronic device 30. In contrast, by using a parameter that does not require direct communication with the electronic device 30, such as power consumption or the amount of power consumption, as a parameter related to the operating state, it becomes possible to calculate the required cooling amount without imposing a processing burden on the electronic device 30. Also, instead of the CPU load rate, a method of estimating the CPU load rate based on a job given to the electronic device 30 may be adopted.

[0050] The calculation unit 52 has an arithmetic expression for the required cooling amount that includes, as variables, parameters related to the operating state of the electronic device 30. Then, the calculation unit 52 calculates the required cooling amount by inputting the detected values ​​of the parameters at each time into this arithmetic expression. For example, when the power consumption is used as a parameter related to the operating state of the electronic device 30, the required cooling amount may be calculated by multiplying the power consumption by a predetermined proportional coefficient. Note that the calculation formula is an example and is not limited to this. For example, the relationship between the parameter related to the operating state of the electronic device 30 and the required cooling amount may be obtained by a pre-test or a simulation. The required cooling amount is determined based on the temperature at which the electronic device 30 can exert a predetermined computing capacity, and is appropriately set according to the required computing capacity.

[0051] The immersion cooling system 1 includes a configuration for detecting parameters relating to the operating state of the electronic device 30. For example, the immersion cooling system 1 has a power consumption meter (not shown) that detects the power consumption of the electronic device 30, and a communication unit (not shown) that transmits a signal output from the power consumption meter to the system control device 40. As the power consumption meter, for example, a known sensor such as a watt monitor that is used by being plugged into an outlet can be used.

[0052] The immersion cooling system 1 may also have a temperature sensor (not shown) that measures the temperature of the electronic device 30, and a communication unit (not shown) that transmits a signal output from the temperature sensor to the system control device 40. The temperature sensor is attached to, for example, a component that generates a large amount of heat in the electronic device 30, and transmits a detected value to the system control device 40 via the communication unit.

[0053] The parameters relating to the operating state of the electronic device 30 may be acquired for each board 11 (for example, for each server), or for each board group (for each server group) made up of a plurality of boards 11. In other words, as long as the parameter values ​​of the entire electronic device 30 immersed in the immersion tank 3 can be obtained, the method of acquisition is not limited.

[0054] The cooling condition setting unit 53 sets a parameter related to the flow rate of the coolant and a parameter related to the temperature of the cooling water and / or a parameter related to the flow rate of the cooling water based on the required cooling amount calculated by the calculation unit 52, for example.

[0055] For example, when the normal mode is selected, the cooling condition setting unit 53 sets the target flow rate of the coolant, the target temperature of the cooling water, and the target flow rate of the cooling water based on the required cooling amount. Here, the target temperature of the cooling water is the target temperature of the cooling water supplied to the heat exchanger 17 (see FIG. 1).

[0056] As an example, the cooling condition setting unit 53 has one or more map information that associates the required cooling amount with the flow rate of the coolant, the temperature of the coolant, and the flow rate of the coolant, and by using this map information, the target flow rate of the coolant, the target temperature of the coolant, and the target flow rate of the coolant are obtained from the required cooling amount.

[0057] As another example, the cooling condition setting unit 53 may have an arithmetic formula for obtaining the target flow rate of the cooling liquid, the target temperature of the cooling water, and the target flow rate of the cooling water from the required cooling amount, and may use this arithmetic formula to calculate the target flow rate of the cooling liquid, the target temperature of the cooling water, and the target flow rate of the cooling water from the required cooling amount. Here, the limit minimum temperature of the cooling water inlet temperature is determined based on external conditions. For example, the limit temperature of the cooling water inlet temperature is a value obtained by adding a predetermined temperature (for example, 5°C) to the outside air wet-bulb temperature. This limit minimum temperature is the limit temperature at which the cooling water can be cooled when the fan 23 is driven at the maximum rotation speed. Therefore, for example, when the target temperature of the cooling water is equal to or lower than the limit minimum temperature determined based on the outside air conditions, the target temperature of the cooling water may be set to the limit minimum temperature, and other parameters, i.e., the target flow rate of the cooling liquid and the target flow rate of the cooling water, may be set so that the required cooling amount is obtained.

[0058] The target rotation speed of the fan 23 is calculated, for example, by using the target temperature of the cooling water (the cooling water inlet temperature of the heat exchanger 17), the cooling water outlet temperature, and the target flow rate of the cooling water in a predetermined arithmetic expression. Here, the cooling amount in the cooling unit 7 is expressed, for example, by the following equation (1). Therefore, the target rotation speed of the fan 23 is set so that the required cooling amount is obtained in the following arithmetic expression. The rotation speed of the fan 23 may also be determined based on an arithmetic expression that further includes the outside air condition (for example, the outside air wet-bulb temperature) as a parameter.

[0059] Cooling amount = (cooling water outlet temperature of heat exchanger - cooling water inlet temperature of heat exchanger) x cooling water flow rate (1)

[0060] For example, when the performance priority mode is selected as the cooling mode, the cooling condition setting unit 53 sets the target temperature of the coolant to the minimum temperature derived from the outside air conditions. The cooling condition setting unit 53 may set the target flow rate of the coolant to the maximum flow rate and set the target rotation speed of the fan 23 to the maximum rotation speed. The cooling condition setting unit 53 may also set the target flow rate of the coolant to the maximum flow rate. As a result, when the performance priority mode is selected, the coolant circulation system 6 is controlled so as to obtain the maximum cooling effect or an effect close to the maximum derived from the outside air conditions.

[0061] In addition, when the energy saving priority mode is selected as the cooling mode, the cooling condition setting unit 53 sets a target temperature of the cooling water based on a predetermined temperature determined based on the heat resistance characteristics of the electronic components that make up the electronic device 30, and may optimize the target flow rate of the cooling liquid, the target flow rate of the cooling water, and the target rotation speed of the fan 23 so as to minimize power consumption and satisfy the set target temperature of the cooling water and the required cooling amount. Here, the "predetermined temperature" is, for example, the lowest allowable maximum temperature among the allowable maximum temperatures of the electronic components immersed in the immersion tank 3, or a temperature that has a predetermined margin above that allowable maximum temperature.

[0062] The target flow rate of the cooling liquid, the target flow rate of the cooling water, and the target rotation speed of the fan 23 can be optimized by using a known optimization method. The cooling condition setting unit 53 may set various target values ​​in order so as to satisfy the required cooling amount based on a predetermined order that has been set in advance. For example, the predetermined order may be the order of the elements that have the highest power reduction effect. For example, if the power of the fan 23, the power of the pump 28, and the power of the pump 19 have the highest power reduction effect in this order, the target values ​​may be set in this order.

[0063] When the cooling conditions are set by the cooling condition setting unit 53 in this manner, the pump 19 of the coolant circulation unit 5 and the pump 28 and fan 23 of the cooling unit 7 are controlled based on the set cooling conditions. Specifically, the electric motor of the pump 19 is controlled at a frequency corresponding to the target flow rate of the coolant, thereby controlling the discharge rate of the pump 19 to the target flow rate. Furthermore, the electric motor of the pump 28 is controlled at a frequency corresponding to the target flow rate of the cooling water, thereby controlling the discharge rate of the pump 28 to the target flow rate. Furthermore, the fan 23 is controlled based on the target rotation speed of the fan 23.

[0064] Next, a control method realized by the system control device 40 according to this embodiment will be described with reference to Figs. 6 and 7. Figs. 6 and 7 are flow charts showing an example of the procedure of the control method for the coolant circulation system 6 according to this embodiment. The series of processes shown below are realized, for example, by a processing circuit. Specifically, the CPU 41 reads out a program stored in the storage unit 43 into the main memory 42 and executes information processing and arithmetic processing.

[0065] Hereinafter, a case will be described in which the power consumption of the electronic device 30 is used as a parameter related to the operating state of the electronic device 30. Various variations are as described above, and the control method according to the present disclosure is not limited to the various processes described below. The following series of processes is repeatedly executed at predetermined time intervals, for example.

[0066] First, the system controller 40 calculates the total power consumption of the electronic equipment 30 immersed in the immersion tank 3 based on the values ​​detected by a power consumption meter (not shown) (SA1).

[0067] Next, the system controller 40 calculates the required amount of cooling by substituting the amount of power consumption into a predetermined calculation formula (SA2).

[0068] Next, it is determined whether the currently selected cooling mode is the normal mode (SA3). As a result, if it is the normal mode (SA3: YES), the cooling conditions are set based on the required cooling amount (SA4). As a result, the target flow rate of the coolant, the target temperature of the coolant, and the target flow rate of the coolant are set based on the required cooling amount. In addition, the target rotation speed of the fan is set based on the target temperature of the coolant, the heat exchanger outlet temperature of the coolant, and the target flow rate of the coolant.

[0069] If the normal mode is not selected as the cooling mode (SA3: NO), it is determined whether or not the performance-priority mode is selected as the cooling mode (SA5). If the performance-priority mode is selected (SA5: YES), the target flow rate of the coolant is set to the maximum flow rate, the target rotation speed of the fan is set to the maximum rotation speed, and the target flow rate of the coolant is set to the maximum flow rate (SA6).

[0070] On the other hand, if the performance priority mode is not selected as the cooling mode (SA5: NO), it is determined that the energy saving mode is selected as the cooling mode, and a target temperature of the cooling water is set based on the minimum value of the maximum allowable temperatures of the multiple electronic components that make up the electronic device 30 (SA7 in FIG. 7). Next, a target flow rate of the cooling liquid, a target flow rate of the cooling water, and a target rotation speed of the fan 23 are set so as to satisfy the set target temperature of the cooling water and the required cooling amount (SA8).

[0071] Next, the pump 19, the pump 28, and the fan 23 are driven based on the set cooling conditions (SA9). For example, various target values ​​are transmitted to drive control units (not shown) that respectively drive the pump 19, the pump 28, and the fan 23, and the drive control units perform drive control according to the target values.

[0072] As a result, the rotation speed of the electric motor that drives pump 19 is controlled based on the target flow rate of the coolant, the rotation speed of the electric motor that drives pump 28 is controlled based on the target flow rate of the cooling water, and the fan 23 is controlled based on its target rotation speed.

[0073] In this way, the pumps 19, 28 and fan 23 are driven and controlled based on the target values, so that the pump 19 sends the cooling liquid to the heat exchanger 17 at a discharge rate according to the required cooling amount, and the cooling liquid is cooled in the heat exchanger 17 to a temperature based on the required cooling amount, so that the cooling liquid is delivered to the immersion tank 3 at a temperature and flow rate that satisfies the required cooling amount.

[0074] The effects of the present embodiment described above are as follows. According to this embodiment, the required cooling amount is calculated based on parameters related to the operating state of the electronic device 30, and the cooling conditions are set taking the required cooling amount into consideration. Since the operating state of the electronic device 30 has a correlation with the amount of heat generated by the electronic device 30, it is possible to calculate the required cooling amount according to the amount of heat generated by the electronic device 30 by using the parameters related to the operating state of the electronic device 30. This makes it possible to set appropriate cooling conditions according to the amount of heat generated by the electronic device. Furthermore, according to this embodiment, a plurality of cooling modes are provided, and the cooling conditions are set based on the selected cooling mode and the required cooling amount, so that appropriate cooling can be performed according to the desired mode.

[0075] For example, when the performance priority mode is selected as the cooling mode, the cooling conditions are set to realize the maximum cooling effect derived from the outside air conditions. This makes it possible to realize the maximum or nearly maximum cooling effect, and to maintain the performance of the electronic device 30 at or above the desired performance.

[0076] Furthermore, when the energy saving priority mode is selected as the cooling mode, the target temperature of the cooling water is set within a range not exceeding a predetermined temperature determined based on the maximum allowable temperature of the electronic components constituting the electronic device 30, and the cooling conditions are set so as to satisfy the target temperature of the cooling water and the required cooling amount, and to minimize power consumption. This makes it possible to keep all of the electronic devices 30 at or below the maximum allowable temperature while suppressing power consumption.

[0077] Second Embodiment Next, a second embodiment of the present disclosure will be described. This embodiment differs from the first embodiment in that a correction unit is provided. Therefore, in the following description, the configuration different from the first embodiment will be mainly described, and the same reference numerals will be used to denote common matters, and the description thereof will be omitted.

[0078] 8 is a functional block diagram showing an example of functions of the system control device 40a according to the present embodiment. As shown in FIG 8, the system control device 40a includes a correction unit 54 that corrects the required cooling amount calculated by the calculation unit 52.

[0079] The correction unit 54 corrects the required cooling amount based on the deviation between the distribution of parameters indicating the operating state for the arrangement of multiple electronic devices 30 in the immersion tank 3 and the distribution of cooling efficiency in the immersion tank 3. The "distribution of parameters indicating the operating state" is, for example, the distribution of power consumption.

[0080] For example, as shown in Fig. 9(a), substrates 11 on which multiple electronic devices 30 are mounted are arranged along the X-axis in the immersion tank 3. For ease of explanation, Fig. 9(a) shows a two-dimensional diagram, but as described above, substrates 11 are also arranged in the depth direction (Y-axis).

[0081] Even if cooling liquid is uniformly supplied from nozzle 32 (see FIG. 3) provided below immersion tank 3, the cooling effect may not be uniform within immersion tank 3 and variations may occur, as shown in FIG. 9(b). That is, there may be positions that are easy to cool and positions that are difficult to cool. In the example shown in FIG. 9(b), the cooling effect is highest in the center of immersion tank 3 and decreases toward the sides. Note that the variation in cooling effect shown in FIG. 9(b) is just one example, and the degree of variation is influenced by various factors such as the structure and shape of immersion tank 3.

[0082] Furthermore, the power consumption of the multiple substrates 11 (electronic devices 30) arranged in the immersion tank 3 also varies depending on their operating conditions. For example, Figs. 9(c) and (d) are diagrams showing examples of the variation (distribution) of the power consumption of the substrates 11 with respect to position. For example, the power consumption distribution shown in Fig. 9(c) shows almost the same tendency as the cooling effect distribution shown in Fig. 9(b), with little deviation. In contrast, the power consumption distribution shown in Fig. 9(d) shows that the power consumption of the substrate 11 arranged in the center is low, and the power consumption of the substrates 11 increases toward the sides. It can be seen that this power consumption distribution has an opposite tendency to the cooling efficiency distribution shown in Fig. 9(b), with a large deviation in the distribution.

[0083] In this embodiment, the required cooling amount is corrected based on the deviation (amount of deviation) between the cooling effect and the amount of power consumption at each position of the immersion tank 3. For example, the correction unit 54 has a preset cooling effect distribution. Then, the power consumption distribution of the entire electronic device 30 is calculated from the power consumption obtained from the power consumption meter, and the calculated power consumption distribution is compared with the cooling effect distribution to calculate the relative deviation of the distribution. The comparison of the distributions may be performed using a known statistical method, such as a method of making each distribution dimensionless based on the average value or standard deviation, or a method of making a comparison after normalizing the distributions.

[0084] In addition, one example of the method for calculating the amount of deviation is to calculate, for each substrate 11, the difference between the dimensionless value of the power consumption at that position and the dimensionless value of the cooling efficiency, and then accumulate the calculated differences to calculate the amount of deviation of the entire distribution.

[0085] Then, the correction unit 54 calculates the correction amount based on the deviation of the distribution calculated by the above-mentioned method and the average power consumption of the entire electronic device 30. For example, the correction unit 54 calculates the correction amount by substituting each calculated value into a correction amount calculation formula including the deviation of the distribution and the average power consumption of the entire electronic device 30 as variables. Here, the correction amount is calculated as a calculation formula in which the larger the deviation, the larger the correction amount. Also, the calculation formula is such that the higher the average power consumption, the smaller the correction amount.

[0086] After calculating the correction amount, the correction unit 54 uses the calculated correction amount to correct the required cooling amount calculated by the calculation unit 52. For example, the required cooling amount is corrected by adding the correction amount to the required cooling amount. In addition, when the correction amount is obtained as a correction coefficient, the required cooling amount may be corrected by multiplying the required cooling amount by the correction coefficient.

[0087] When the required cooling amount is corrected in this manner, the corrected required cooling amount is output to the cooling condition setting unit 53, and the cooling conditions are set using this corrected required cooling amount.

[0088] As described above, according to this embodiment, the system control device 40a includes a correction unit 54 that corrects the required cooling amount based on a deviation between the distribution of parameters (e.g., distribution of power consumption) indicating the operating state for the positions of the multiple electronic devices 30 in the immersion tank 3 and the distribution of cooling efficiency for the positions in the immersion tank 3. This makes it possible to set appropriate cooling conditions taking into consideration the variation in heat generation and the variation in cooling efficiency of the electronic devices 30 in the immersion tank 3.

[0089] As a distribution of parameters indicating the operating state, a distribution of CPU load factors estimated from the execution status of a computing job given to each board 11 (each server) may be used. As with the power consumption amount described above, the CPU load factor also has a correlation with the amount of heat generated by the electronic device 30. Therefore, instead of the power consumption amount, a distribution based on the CPU load factor may be calculated, and the calculated distribution of the CPU load factor may be compared with the cooling effect distribution to calculate the deviation amount therebetween. Also, the correction amount is calculated using the deviation amount of the distribution and the average value of the CPU load factor, as described above.

[0090] FIG. 10 is a diagram showing an example of the change over time in the computation jobs given to each board 11 (first board to fifth board). If the computation load of the computation job is high, the CPU load rate increases, and if the computation load of the computation job is low, the CPU load rate decreases. For example, focusing on time T1, the CPU loads of the second and third boards are higher than those of the first, fourth, and fifth boards. For this reason, it is estimated that at time T1, the heat generation amounts of the second and third boards will be greater than those of the other boards.

[0091] Furthermore, the amount of heat generated by the electronic device 30 changes gradually compared to changes in the CPU load factor. Therefore, the average value of the CPU load factor in a predetermined period may be calculated for each board 11, and the distribution of the average values ​​may be used to compare with the cooling effect distribution.

[0092] In this way, by estimating the CPU load rate from the calculation job and calculating the correction amount using the distribution of the estimated CPU load rate, it is possible to set the cooling conditions taking into account the future operating state of the electronic device 30.

[0093] Third Embodiment Next, a third embodiment of the present disclosure will be described. In the embodiment, in addition to the first embodiment, as shown in Fig. 11, a flow rate adjustment unit 34 is provided for each nozzle 32, and as shown in Fig. 12, a system control device 40b includes a nozzle flow rate control unit 55. In the following description, configurations that differ from the first embodiment will be mainly described, and common items will be given the same reference numerals and description thereof will be omitted.

[0094] 11, in the immersion cooling system 1 according to this embodiment, a flow rate adjuster 34 is provided for each nozzle 32. The flow rate adjuster 34 adjusts the flow rate of the cooling liquid Lq discharged from the nozzle 32. An example of the flow rate adjuster 34 is a flow rate adjustment valve. The flow rate adjuster 34 is controlled by a system control device 40b.

[0095] 12 is a functional block diagram showing an example of functions of the system control device 40b according to the present embodiment. As shown in FIG. 12, the system control device 40b includes a nozzle flow rate control unit 55.

[0096] 9(b), for example, the nozzle flow rate control unit 55 controls the flow rate adjustment unit 34 so as to make the cooling efficiency uniform. For example, the nozzle flow rate control unit 55 increases the valve opening of the flow rate adjustment unit 34 corresponding to a position where the cooling efficiency is lower than a predetermined value (for example, an average value) to increase the amount of coolant discharged, while narrowing the valve opening of the flow rate adjustment unit 34 corresponding to a position where the cooling effect is higher than a predetermined value to decrease the amount of coolant discharged. This makes it possible to reduce the variation in the cooling efficiency in the immersion tank 3.

[0097] Furthermore, instead of the above control, for example, the nozzle flow rate control unit 55 may control the valve opening degree of the flow rate adjustment unit 34 in accordance with the difference between the power consumption distribution and the cooling effect distribution in the immersion tank 3. The method of calculating the difference in distribution is as described in the second embodiment. In this way, by comparing the power consumption distribution with the cooling effect distribution, the difference in distribution at the position of each substrate 11 is calculated, and the valve opening of the flow rate adjustment unit 34 is adjusted according to this difference. For example, for a position where the cooling effect is relatively low but the power consumption is relatively high, the valve opening of the flow rate adjustment unit 34 is opened to increase the discharge amount of the cooling liquid, thereby making it possible to reduce the difference between the power consumption and the cooling effect. Similarly, for a position where the cooling effect is relatively high but the power consumption is relatively low, the valve opening of the flow rate adjustment unit 34 is narrowed to reduce the discharge amount of the cooling liquid, thereby making it possible to reduce the difference between the power consumption and the cooling effect. In this way, by controlling the flow rate adjusters 34 provided corresponding to the respective nozzles, it becomes possible to perform precise cooling control according to the position. As described in the second embodiment, the CPU load rate may be used instead of the power consumption.

[0098] [Fourth embodiment] Next, a fourth embodiment of the present disclosure will be described. In the first embodiment, the system control device 40 sets the target flow rate of the coolant, the target flow rate of the cooling water, and the target temperature of the cooling water. In other words, the system control device 40 controls both the coolant circulation unit 5 and the cooling unit 7. In contrast, the present embodiment is different in that it has a cooling unit control unit 60 that controls the cooling unit 7, and a coolant circulation unit control unit 70 that controls the coolant circulation unit 5. In the following description, configurations that differ from the first embodiment will be mainly described, and common items will be given the same reference numerals and description thereof will be omitted.

[0099] 13 is a functional block diagram showing an example of functions of the cooling unit control unit 60. In this embodiment, the cooling unit 7 includes, for example, the cooling unit control unit 60. In addition, the coolant circulation unit 5 includes a coolant circulation unit control unit 70. The cooling unit control unit 60 and the coolant circulation unit control unit 70 may be configured to be capable of communicating with each other. This allows the cooling unit control unit 60 to obtain information on the flow rate of the coolant from the coolant circulation unit control unit 70, for example.

[0100] Examples of information related to the flow rate of the coolant include a target flow rate of the coolant, a detection value of a flow rate sensor of the coolant, or the rotation speed or frequency of the pump 19 that controls the flow rate of the coolant. Below, an example will be described in which the target flow rate of the coolant is used as information related to the flow rate of the coolant. When the rotation speed or frequency of the pump 19 is used as information related to the flow rate of the coolant, the flow rate of the coolant can be estimated from the rotation speed or frequency of the pump 19. In this embodiment, the flow rate of the cooling liquid may be controlled to be constant.

[0101] The cooling unit control unit 60 includes, for example, a mode selection unit 51, a calculation unit 52, and a cooling condition setting unit 53a. The cooling condition setting unit 53a sets a target temperature and a target flow rate of the cooling water based on the cooling mode selected by the mode selection unit 51 and the required cooling amount calculated by the calculation unit 52.

[0102] For example, when the normal mode is selected as the cooling mode, the cooling condition setting unit 53a sets the target temperature and the target flow rate of the cooling water based on the required cooling amount and the target flow rate of the cooling water. These settings can be set, for example, by using a value acquired from the cooling liquid circulation unit control unit 70 as the flow rate of the cooling water in the various calculation methods described in the first embodiment. Note that, when the cooling liquid circulation unit control unit 70 controls the pump 19 at a constant discharge rate, the control value (target flow rate, etc.) may be registered in advance, and the target temperature and target flow rate of the cooling water may be set using the registered control value. In such a case, communication with the cooling liquid circulation unit control unit 70 is also not required.

[0103] For example, when the performance priority mode is selected as the cooling mode, the cooling condition setting unit 53a sets the target temperature of the cooling water to the minimum temperature derived from the outside air conditions. For example, the cooling condition setting unit 53a may set the target rotation speed of the fan 23 to the maximum rotation speed. Furthermore, the cooling condition setting unit 53 may also set the target flow rate of the cooling water to the maximum flow rate. As a result, when the performance-first mode is selected, the cooling unit 7 is controlled so as to obtain the maximum cooling effect or an effect close to the maximum that is derived from the outside air conditions.

[0104] Furthermore, when the energy saving priority mode is selected, the cooling condition setting unit 53a sets the target temperature of the cooling water based on a predetermined temperature determined based on the heat resistance characteristics of the electronic components constituting the electronic device 30. Furthermore, the cooling condition setting unit 53a sets the target flow rate of the cooling water and the target rotation speed of the fan 23 that satisfy the set target temperature of the cooling water and the required cooling amount, using the target flow rate of the cooling water acquired from the cooling liquid circulation unit control unit 70 or a target flow rate of the cooling liquid registered in advance. At this time, it is preferable to set the target flow rate of the cooling water and the target rotation speed of the fan 23 so that the power of the pump 28 and the fan 23 is minimized. The optimization of the target flow rate of the cooling medium and the target rotation speed of the fan 23 can be realized by using a known optimization method.

[0105] The cooling condition setting unit 53a may set various target values ​​in order to satisfy the required cooling amount based on a predetermined order that has been set in advance. For example, the predetermined order may be the order of the elements that have the highest power reduction effect. For example, if the power of the fan 23 is the most effective in reducing power, followed by the power of the pump 28, the target values ​​may be set in this order.

[0106] The cooling conditions (e.g., the target rotation speed of the pump 28 and the target rotation speed of the fan 23) set by the cooling condition setting unit 53a in this manner are transmitted to a drive control unit (not shown) that drives the pump 28 and the fan 23 of the cooling unit 7, and these are driven according to the target values.

[0107] In this way, according to this embodiment, the required cooling amount is calculated based on parameters related to the operating state of the electronic device 30, and the cooling conditions are set in consideration of the required cooling amount. Since the operating state of the electronic device 30 has a correlation with the amount of heat generated by the electronic device 30, it is possible to calculate the required cooling amount according to the amount of heat generated by the electronic device 30 by using parameters related to the operating state of the electronic device 30. This makes it possible to set appropriate cooling conditions for the cooling unit 7 according to the amount of heat generated by the electronic device 30. Furthermore, according to this embodiment, multiple cooling modes are provided, and cooling conditions are set based on the selected cooling mode and the required cooling amount, making it possible to appropriately control the cooling unit 7 according to the mode.

[0108] For example, when the performance priority mode is selected as the cooling mode, the cooling conditions of the cooling unit 7 are set to realize the maximum cooling effect derived from the outside air conditions. This allows the cooling unit 7 to exert its maximum or nearly maximum cooling capacity.

[0109] Furthermore, when the energy saving priority mode is selected as the cooling mode, a target temperature of the cooling water is set within a range not exceeding a predetermined temperature determined based on the maximum allowable temperature of the electronic components constituting the electronic device 30, and further, the cooling conditions of the cooling unit 7 are set so as to satisfy the target temperature of the cooling water and the required cooling amount, and to minimize the power consumption of the cooling unit 7. This makes it possible to keep all of the electronic devices 30 at or below the maximum allowable temperature while suppressing the power consumption of the cooling unit 7.

[0110] In the above-described fourth embodiment, the cooling unit control section 60 may further include a correction section 54. Details of the correction section 54 have been described in detail in the second embodiment, and therefore will not be described here.

[0111] In the fourth embodiment, the cooling unit control section 60 and the coolant circulation unit control section 70 may be realized by the same processing circuit, or may be realized by different processing circuits (in other words, different computers).

[0112] Fifth embodiment Next, a fifth embodiment of the present disclosure will be described. In the first embodiment, the system control device 40 sets the target flow rate of the coolant, the target flow rate of the cooling water, and the target temperature of the cooling water. In other words, the system control device 40 controls both the coolant circulation unit 5 and the cooling unit 7. In contrast, the present embodiment is different in that it has a cooling unit control unit 60a that controls the cooling unit 7, and a coolant circulation unit control unit 70a that controls the coolant circulation unit 5. In the following description, configurations that differ from the first embodiment will be mainly described, and common items will be given the same reference numerals and description thereof will be omitted.

[0113] 14 is a functional block diagram showing an example of functions of the coolant circulation unit control unit 70a. In this embodiment, the cooling unit 7 includes, for example, a cooling unit control unit 60a. The coolant circulation unit 5 includes a coolant circulation unit control unit 70a. The cooling unit control unit 60a and the coolant circulation unit control unit 70a may be configured to be capable of communicating with each other, which allows the coolant circulation unit control unit 70a to obtain information on the temperature and flow rate of the coolant from the cooling unit control unit 60a, for example.

[0114] The coolant circulation unit control unit 70a includes, for example, a mode selection unit 51, a calculation unit 52, and a cooling condition setting unit 53b. The cooling condition setting unit 53b sets a target flow rate of the coolant based on the cooling mode selected by the mode selection unit 51 and the required cooling amount calculated by the calculation unit 52.

[0115] For example, when the normal mode is selected as the cooling mode, the cooling condition setting unit 53b sets a target flow rate of the cooling liquid based on the required cooling amount calculated by the calculation unit 52, the inlet temperature of the cooling liquid flowing into the heat exchanger 17, and the outlet temperature of the cooling liquid discharged from the heat exchanger 17. For example, the amount of cooling is expressed by the following formula.

[0116] Cooling amount = (coolant inlet temperature - coolant outlet temperature) × coolant flow rate (2)

[0117] The cooling condition setting unit 53b calculates the coolant flow rate by substituting the required cooling amount for the cooling amount, the coolant inlet temperature, and the coolant outlet temperature for the cooling amount and the temperature sensor detection values ​​for the coolant inlet temperature and the coolant outlet temperature in the above equation (2), and sets the calculated coolant flow rate as the target flow rate.

[0118] Furthermore, for example, when the performance-priority mode is selected as the cooling mode, the cooling condition setting unit 53b sets the target flow rate of the coolant to the maximum flow rate. In this way, when the performance-priority mode is selected, the target flow rate of the coolant is set to the maximum flow rate, thereby controlling the coolant circulation unit 5 so that the maximum cooling capacity can be achieved.

[0119] In addition, when the energy saving priority mode is selected as the cooling mode, the cooling condition setting unit 53b sets the target temperature of the coolant based on a predetermined temperature determined based on the heat resistance characteristics of the electronic components that make up the electronic device 30, and sets the target flow rate of the coolant to the minimum flow rate of the coolant that satisfies the required cooling amount. Here, the "predetermined temperature" is, for example, the lowest allowable maximum temperature among the allowable maximum temperatures of the electronic components immersed in the immersion tank 3, or a temperature that has a predetermined margin above that allowable maximum temperature.

[0120] For example, in the above equation (2), the cooling condition setting unit 53b substitutes the required cooling amount for the cooling amount, the detected value of the temperature sensor for the coolant inlet temperature, and the above "target temperature of the coolant" for the coolant outlet temperature to calculate the coolant flow rate for obtaining the required cooling amount, and sets the calculated coolant flow rate as the target flow rate.

[0121] The cooling conditions thus set by the cooling condition setting unit 53b are transmitted to a drive control unit (not shown) that drives the pump 19 of the coolant circulation unit 5, and the drive of the pump 19 is controlled in accordance with the cooling conditions.

[0122] In this way, according to this embodiment, the required cooling amount is calculated based on parameters related to the operating state of the electronic device 30, and the cooling conditions are set taking the required cooling amount into consideration. Since the operating state of the electronic device 30 has a correlation with the amount of heat generated by the electronic device 30, it is possible to calculate the required cooling amount according to the amount of heat generated by the electronic device 30 by using parameters related to the operating state of the electronic device 30. This makes it possible to set appropriate cooling conditions for the coolant circulation unit 5 according to the amount of heat generated by the electronic device 30. Furthermore, according to this embodiment, multiple cooling modes are provided, and the cooling conditions are set based on the selected cooling mode and the required cooling amount, making it possible to appropriately control the coolant circulation unit 5 according to the mode.

[0123] For example, when the performance priority mode is selected as the cooling mode, the target flow rate of the coolant is set to the maximum flow rate, which allows the coolant circulation unit 5 to maximize its cooling capacity.

[0124] Furthermore, when the energy saving priority mode is selected as the cooling mode, the coolant discharge temperature is set based on a predetermined temperature determined based on the heat resistance characteristics of the electronic components constituting the electronic device 30, and the target flow rate of the coolant is set to the minimum flow rate of the coolant that satisfies the required cooling amount. This makes it possible to keep all of the electronic devices 30 at or below the maximum allowable temperature while suppressing the power consumption of the coolant circulation unit 5.

[0125] In the above-described fifth embodiment, the coolant circulation unit control section 70a may further include a correction section 54. Details of the correction section 54 have been described in detail in the second embodiment, and therefore will not be described here.

[0126] In the fifth embodiment, the cooling unit controller 60a and the coolant circulation unit controller 70a may be realized by the same processing circuit, or may be realized by different processing circuits (in other words, different computers).

[0127] In the above-described fifth embodiment, the coolant circulation system 6 has the cooling unit 7, but the cooling unit 7 may be omitted. In this case, the heat exchanger 17 in the coolant circulation unit 5 is an air-cooled heat exchanger that exchanges heat with outside air. In this case, the control by the coolant circulation unit control unit 70a is the same as described above.

[0128] In the fifth embodiment, the coolant outlet temperature sent from the heat exchanger 17 is detected by a temperature sensor, and the target flow rate of the coolant is set using the detected value, but this is not limited to this. For example, if the cooling unit control unit 60a and the coolant circulation unit control unit 70a are configured to be able to communicate with each other, the target temperature and target flow rate of the coolant may be obtained from the cooling unit control unit 60a, and the coolant outlet temperature may be estimated using the obtained information. By estimating the coolant outlet temperature in this way, it is possible to omit a temperature sensor that measures the coolant outlet temperature.

[0129] Although the embodiments of the present disclosure have been described above, the technical scope of the present disclosure is not limited to the scope described in the above embodiments. Various modifications or improvements can be made to the above embodiments without departing from the gist of the disclosure, and the forms in which such modifications or improvements are made are also included in the technical scope of the present disclosure. In addition, the above embodiments may be appropriately combined. Furthermore, the processing procedures shown in FIGS. 6 and 7 are also examples, and unnecessary steps may be deleted, new steps may be added, or the processing order may be changed as appropriate.

[0130] In the above-described embodiments, the flow rate of the coolant is controlled by the pump 19, and the flow rate of the cooling water is controlled by the pump 28. However, the flow rate control of the coolant and the cooling water is not limited to this. For example, the discharge rate of the pump 19 may be constant, in other words, the pump 19 may be a fixed-speed pump, and a flow rate adjustment unit for adjusting the flow rate may be provided in the cooling liquid circulation path. Similarly, the discharge rate of the pump 28 may be constant, in other words, the pump 28 may be a fixed-speed pump, and a flow rate adjustment unit for adjusting the flow rate may be provided in the cooling water circulation path. An example of the flow rate adjustment unit is a flow rate adjustment valve.

[0131] In addition, in each of the above-described embodiments, the cooling medium that exchanges heat with the cooling liquid is exemplified as cooling water, but the cooling medium is not limited to this example. A liquid other than water may be used as the cooling medium.

[0132] In each of the above-described embodiments, the cooling unit 7 has been described by way of example in which the cooling water is directly cooled by the outside air taken in by the fan 23, but the present invention is not limited to this example. For example, the cooling unit 7 may be configured to cool the cooling water using a refrigerant such as water, such as a chiller, as a cooling section. In this case, the cooling condition setting section according to each embodiment may set parameters for controlling the cooling section. More specifically, the cooling condition setting section sets the amount of circulation of the refrigerant for cooling the cooling water, instead of the rotation speed of the fan 23.

[0133] In the above-described second embodiment and the like, when the system control device includes the correction unit 54, it is possible to omit the mode selection unit 51. In this case, the cooling conditions are set according to the control when the cooling mode is set to the normal mode.

[0134] In addition, in each of the above-described embodiments, the temperature and flow rate of the coolant are controlled according to the operating state of the electronic device 30, but instead of this, for example, the computation job given to the electronic device 30 may be controlled according to the cooling state. For example, as shown in Fig. 9(b), when the cooling efficiency varies depending on the position, a computation job with a high computation load may be assigned to a board 11 (server) arranged at a position with high cooling efficiency, and a computation job with a low computation load may be assigned to a board 11 (server) arranged at a position with low cooling efficiency.

[0135] The coolant circulation unit and the control method and program thereof described in each of the above-described embodiments can be understood, for example, as follows.

[0136] A coolant circulation unit (5) according to one embodiment of the present disclosure is a coolant circulation unit that circulates a coolant through an immersion tank (3) in which multiple electronic devices (30) are immersed in the coolant to cool them, and includes a flow rate adjustment unit (19) provided in a coolant circulation path that circulates the coolant through the immersion tank, a heat exchanger (17) provided in the coolant circulation path and performing heat exchange between the coolant and a cooling medium, and a coolant circulation unit control unit (70a). The coolant circulation unit control unit includes a mode selection unit (51) that selects one of multiple cooling modes, a calculation unit (52) that calculates a required amount of cooling based on parameters related to the operating states of the multiple electronic devices, and a cooling condition setting unit (53b) that sets a target value of a parameter related to the flow rate of the coolant based on the selected cooling mode and the required amount of cooling.

[0137] In this way, the required cooling amount is calculated based on the parameters related to the operating state of the electronic device, and the cooling conditions are set taking the required cooling amount into consideration. Since the operating state of the electronic device is correlated with the amount of heat generated by the electronic device, it is possible to calculate the required cooling amount according to the amount of heat generated by the electronic device by using the parameters related to the operating state of the electronic device. This makes it possible to set appropriate cooling conditions for the coolant circulation unit according to the amount of heat generated by the electronic device. Furthermore, since a plurality of cooling modes are provided and the cooling conditions are set based on the selected cooling mode and the required cooling amount, it is possible to perform appropriate cooling according to the desired mode.

[0138] In a coolant circulation unit (5) according to one embodiment of the present disclosure, the multiple cooling modes may include a performance priority mode that prioritizes performance of the electronic device, and the cooling condition setting unit may set the target flow rate of the coolant to a maximum flow rate when the performance priority mode is selected.

[0139] This allows the coolant circulation unit to perform at or near its maximum cooling capacity.

[0140] In a coolant circulation unit (5) according to one embodiment of the present disclosure, the multiple cooling modes include an energy saving priority mode that prioritizes power usage efficiency, and when the energy saving priority mode is selected, the cooling condition setting unit may set the temperature at which the coolant is sent to the immersion bath based on a predetermined temperature that is determined based on the heat resistance characteristics of the electronic components that make up the electronic device, and set the target flow rate of the coolant to the minimum flow rate of the coolant that satisfies the required cooling amount.

[0141] This makes it possible to keep all electronic devices below their maximum allowable temperature while reducing the power consumption of the coolant circulation unit.

[0142] In a coolant circulation unit (5) according to one embodiment of the present disclosure, the coolant circulation unit control unit may include a correction unit that corrects the required cooling amount based on a deviation between a distribution of a parameter indicating the operating state of multiple electronic devices for an arrangement in the immersion tank and a distribution of cooling efficiency in the immersion tank, and the cooling condition setting unit may set a target value of a parameter related to the flow rate of the coolant based on a selected cooling mode and the corrected required cooling amount.

[0143] Parameters indicating the operating state of electronic devices are correlated with the amount of heat generated by the electronic devices, and therefore, by comparing the distribution of such parameters with the cooling effect distribution and correcting the required amount of cooling based on the deviation between them, it becomes possible to set appropriate cooling conditions that take into account the variation in the amount of heat generated by the electronic devices and the variation in cooling efficiency in the immersion bath.

[0144] In a coolant circulation unit (5) according to one embodiment of the present disclosure, the correction unit may correct the required amount of cooling based on a deviation between the power consumption distribution for the arrangement of multiple electronic devices in the immersion tank and the cooling efficiency distribution in the immersion tank.

[0145] Since the power consumption is correlated with the amount of heat generated by the electronic devices, it is possible to set appropriate cooling conditions that take into account the variation in the amount of heat generated by the electronic devices and the variation in cooling efficiency in the immersion bath by comparing the power consumption distribution with the cooling effect distribution and correcting the required cooling amount based on the deviation between them.

[0146] In a cooling liquid circulation unit (5) according to one embodiment of the present disclosure, the correction unit may correct the required amount of cooling based on the deviation between the power consumption distribution for the arrangement of multiple electronic devices in the immersion tank and the cooling efficiency distribution in the immersion tank, and the average value of the power consumption of the multiple electronic devices.

[0147] This makes it possible to correct the required cooling amount by taking into account not only the deviation between the power consumption distribution for the arrangement of multiple electronic devices in the immersion tank and the cooling efficiency distribution in the immersion tank, but also the average power consumption of the multiple electronic devices in the immersion tank.

[0148] In a coolant circulation unit (5) according to one embodiment of the present disclosure, the correction unit may correct the required amount of cooling based on a deviation between the calculation load distribution for the arrangement of multiple electronic devices in the immersion tank and the cooling efficiency distribution in the immersion tank.

[0149] The computation load of an electronic device correlates with the amount of heat generated by the electronic device, and therefore, by comparing the computation load distribution with the cooling effect distribution and correcting the required amount of cooling based on the deviation between them, it becomes possible to set appropriate cooling conditions that take into account the variation in the amount of heat generated by the electronic device and the variation in cooling efficiency in the immersion bath.

[0150] In a coolant circulation unit (5) according to one embodiment of the present disclosure, the correction unit may correct the required amount of cooling based on the deviation between the calculation load distribution for the arrangement of multiple electronic devices in the immersion tank and the cooling efficiency distribution in the immersion tank, and the average value of the calculation loads of the multiple electronic devices.

[0151] This makes it possible to correct the required cooling amount by taking into account not only the deviation between the computational load distribution for the arrangement of multiple electronic devices in the immersion tank and the cooling efficiency distribution in the immersion tank, but also the average computational load rate of the multiple electronic devices in the immersion tank. Here, examples of the "computational load" include a computational load rate, a CPU load rate, and the like.

[0152] In the coolant circulation unit (5) according to an aspect of the present disclosure, the calculation load distribution may be estimated based on parameters relating to the execution status of calculation jobs given to a plurality of electronic devices.

[0153] By calculating the correction amount using the calculation load distribution obtained from the calculation job, it becomes possible to set the cooling conditions taking into account the future operating state of the electronic device.

[0154] A control method for a coolant circulation unit (5) according to one embodiment of the present disclosure is a control method for a coolant circulation unit that circulates a coolant through an immersion tank in which multiple electronic devices are immersed in the coolant to cool them, the coolant circulation unit including a flow rate adjustment unit provided in a coolant circulation path that circulates the coolant through the immersion tank, and a heat exchanger provided in the coolant circulation path and performing heat exchange between the coolant and a cooling medium, the control method including the steps of selecting one of multiple cooling modes, calculating a required amount of cooling based on parameters related to the operating state of the multiple electronic devices, and setting a target value for a parameter related to the flow rate of the coolant based on the selected cooling mode and the required amount of cooling.

[0155] A program according to one aspect of the present disclosure is a program for causing a computer to function as the above-described coolant circulation unit control unit.

[0156] An immersion cooling system (1) according to one aspect of the present disclosure includes the above-described cooling liquid circulation unit (5) and an immersion tank (3). [Explanation of symbols]

[0157] 1: Immersion cooling system 3:Immersion tank 5: Coolant circulation unit 6: Coolant circulation system 7: Cooling unit 11: Substrate 13: Liquid supply pipe 15:Return pipe 17:Heat exchanger 19: Pump 21: Coolant discharge pipe 23: Fan 25: Cooling water supply pipe 26: Cooling water return pipe 28: Pump 30:Electronic equipment 32: Nozzle 34:Flow rate adjustment section 40: System control device 40a: System control device 40b: System control device 41: CPU 42: Main memory 43: Storage section 45: Communications Department 46: Input section 47: Display section 51: Mode selection section 52: Calculation section 53: Cooling condition setting section 53a: Cooling condition setting section 53b: Cooling condition setting section 54: Correction section 55: Nozzle flow control section 60: Cooling unit control section 60a: Cooling unit control section 70: Coolant circulation unit control section 70a: Coolant circulation unit control section Lq: Coolant

Claims

1. A cooling liquid circulation unit that circulates a cooling liquid through an immersion tank in which a plurality of electronic devices are immersed in the cooling liquid to be cooled, a flow rate adjusting unit provided in a coolant circulation path that circulates a coolant through the immersion tank; a heat exchanger provided in the cooling liquid circulation path for exchanging heat between the cooling liquid and the cooling medium; Coolant circulation unit control section Equipped with The coolant circulation unit control section includes: A mode selection unit that selects one of a plurality of cooling modes; A calculation unit that calculates a required cooling amount based on parameters related to the operating states of the plurality of electronic devices; a cooling condition setting unit that sets a target value of a parameter related to a flow rate of the cooling liquid based on the selected cooling mode and the required cooling amount; Equipped with The plurality of cooling modes include an energy saving priority mode that prioritizes power usage efficiency, the cooling condition setting unit, when the energy saving priority mode is selected, sets the temperature at which the cooling liquid is delivered to the immersion bath based on a predetermined temperature that is determined based on the heat resistance characteristics of electronic components that constitute the electronic device, and a cooling liquid circulation unit that sets a target flow rate of the cooling liquid to the minimum flow rate of the cooling liquid that satisfies the required cooling amount.

2. the plurality of cooling modes include a performance-prioritized mode that prioritizes performance of the electronic device; The coolant circulation unit according to claim 1 , wherein the cooling condition setting unit sets the target flow rate of the coolant to a maximum flow rate when the performance-priority mode is selected.

3. A cooling liquid circulation unit that circulates a cooling liquid through an immersion tank in which a plurality of electronic devices are immersed in the cooling liquid to cool them, a flow rate adjusting unit provided in a coolant circulation path that circulates a coolant through the immersion tank; a heat exchanger provided in the cooling liquid circulation path for exchanging heat between the cooling liquid and the cooling medium; Coolant circulation unit control section Equipped with The coolant circulation unit control section includes: A mode selection unit that selects one of a plurality of cooling modes; A calculation unit that calculates a required cooling amount based on parameters related to the operating states of the plurality of electronic devices; a correction unit that corrects the required cooling amount based on a deviation between a distribution of a parameter indicating an operating state of the electronic devices relative to an arrangement of the electronic devices in the immersion tank and a distribution of cooling efficiency in the immersion tank; a cooling condition setting unit that sets a target value of a parameter related to a flow rate of the cooling liquid based on the selected cooling mode and the corrected required cooling amount; A cooling liquid circulation unit comprising:

4. The coolant circulation unit according to claim 3 , wherein the correction unit corrects the required cooling amount based on a deviation between a power consumption distribution for an arrangement of the plurality of electronic devices in the immersion tank and a cooling efficiency distribution in the immersion tank.

5. The cooling liquid circulation unit according to claim 3, wherein the correction unit corrects the required cooling amount based on the deviation between the power consumption distribution for the arrangement of the multiple electronic devices in the immersion tank and the cooling efficiency distribution in the immersion tank and the average power consumption of the multiple electronic devices.

6. The coolant circulation unit according to claim 3 , wherein the correction unit corrects the required cooling amount based on a deviation between a calculation load distribution for an arrangement of the plurality of electronic devices in the immersion tank and a cooling efficiency distribution in the immersion tank.

7. The cooling liquid circulation unit according to claim 3, wherein the correction unit corrects the required cooling amount based on the deviation between the calculation load distribution for the arrangement of the plurality of electronic devices in the immersion tank and the cooling efficiency distribution in the immersion tank and the average value of the calculation loads of the plurality of electronic devices.

8. 8. The coolant circulation unit according to claim 6, wherein the calculation load distribution is estimated based on parameters relating to execution status of calculation jobs given to the plurality of electronic devices.

9. 1. A method for controlling a coolant circulation unit that circulates a coolant through an immersion tank in which a plurality of electronic devices are immersed and cooled, comprising the steps of: The coolant circulation unit includes: a flow rate adjusting unit provided in a coolant circulation path that circulates a coolant through the immersion tank; a heat exchanger provided in the cooling liquid circulation path for exchanging heat between the cooling liquid and the cooling medium; Equipped with The control method includes: a mode selection step of selecting one of a plurality of cooling modes; A calculation step of calculating a required cooling amount based on parameters related to the operating states of the plurality of electronic devices; a cooling condition setting step of setting a target value of a parameter related to a flow rate of the cooling liquid based on the selected cooling mode and the required cooling amount; having The plurality of cooling modes include an energy saving priority mode that prioritizes power usage efficiency, The cooling condition setting process is a control method for a coolant circulation unit, which, when the energy saving priority mode is selected, sets the temperature at which the coolant is discharged to the immersion bath based on a predetermined temperature that is determined based on the heat resistance characteristics of electronic components that constitute the electronic device, and sets a target flow rate of the coolant to the minimum flow rate of the coolant that satisfies the required cooling amount.

10. A method for controlling a coolant circulation unit that circulates a coolant through an immersion tank that cools a plurality of electronic devices by immersing them in the coolant, comprising: The coolant circulation unit includes: a flow rate adjusting unit provided in a coolant circulation path that circulates a coolant through the immersion tank; a heat exchanger provided in the cooling liquid circulation path for exchanging heat between the cooling liquid and the cooling medium; Equipped with The control method includes: a mode selection step of selecting one of a plurality of cooling modes; A calculation step of calculating a required cooling amount based on parameters related to the operating states of the plurality of electronic devices; a correcting step of correcting the required cooling amount based on a deviation between a distribution of a parameter indicating an operating state of the electronic devices with respect to an arrangement in the immersion tank and a distribution of cooling efficiency in the immersion tank; a cooling condition setting step of setting a target value of a parameter related to a flow rate of the cooling liquid based on the selected cooling mode and the corrected required cooling amount; A method for controlling a coolant circulation unit having the above structure.

11. A program for causing a computer to function as the coolant circulation unit control unit according to any one of claims 1 to 8.

12. A cooling liquid circulation unit according to any one of claims 1 to 8, The immersion tank.

1. A liquid immersion cooling system comprising:

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