Computer equipment cooling system

Abstract

To provide a computer equipment cooling system which offers superior maintainability and high power utilization efficiency.SOLUTION: A computer equipment cooling system of the present invention comprises a slurry tank for storing slurry ice produced by a slurry ice machine, a pump for pumping the slurry ice, a line for circulating the slurry ice, and a cooling device configured to allow the slurry ice to flow in, where the slurry ice flowing out of the cooling device returns to the slurry tank.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cooling system for computer equipment. [Background technology]

[0002] Large computers, especially supercomputers and data centers, generate a large amount of heat, so proper temperature management is required. Air-cooling and liquid-cooling systems have traditionally been used to cool supercomputers and data centers. Patent Document 1 discloses an air-cooling system that prevents the occurrence of hot spots by adjusting the amount of cool air blown out to the front of the rack according to the amount of heat generated by the server estimated from the server's operating rate. Patent document 2 discloses a cooling unit in which a liquid cooling plate connected to a peripheral device of a server system receives coolant for cooling the peripheral device from a liquid distribution channel and returns the warmed liquid to the liquid distribution channel. Patent Document 3 describes a liquid-cooled data center having coolant supply lines. The liquid-cooled data center is configured so that each row of cabinets housing computer equipment receives coolant from alternating coolant supply lines. If the amount of coolant supplied from one coolant supply line becomes insufficient, the supply of coolant from the other coolant supply line can be increased to equalize the temperature within the multiple cabinets. Patent Document 4 describes a technique of immersion cooling for cooling data centers, in which a server system including computer components (e.g., processors, memory, storage devices) is housed in an immersion tank and immersed in an internal cooling fluid. The internal cooling fluid is a thermally conductive dielectric liquid designed to draw heat from the server system. Typical dielectrics suitable for immersion cooling are typically oil-based. Patent Document 5 describes an immersion cooling device for cooling supercomputers and data centers that uses a fluorocarbon compound, which has electrical insulation properties and a high boiling point, as the coolant, rather than synthetic oil, which makes it difficult to remove electronic devices from the cooling tank for maintenance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-226737 [Patent Document 2] Japanese Patent Publication No. 2022-78287 [Patent Document 3] Special Publication No. 2014-503863 [Patent Document 4] Japanese Patent Publication No. 2022-84812 [Patent Document 5] Patent No. 5956100 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the invention of Patent Document 1 uses air-cooling, which has a smaller heat capacity than liquid and is inferior in performance as a refrigerant, and furthermore, it may be difficult to eliminate uneven temperature distribution such as hot spots. Furthermore, in the inventions of Patent Documents 2 and 3, although cooling water, which has traditionally been used as a coolant, has a higher heat capacity than air, it cannot be set at a temperature below freezing, and therefore it is prone to becoming hot and evaporating. Furthermore, the inventions of Patent Documents 4 and 5 use a liquid immersion method in which the coolant directly contacts the electronic device, making it more difficult to remove the electronic device from the immersion tank and perform maintenance than with other methods.

[0005] An object of the present invention is to provide a cooling system for computer equipment that is easy to maintain and has high power usage efficiency. [Means for solving the problem]

[0006] The invention described in claim 1 is a cooling system for computer equipment comprising a slurry tank for storing ice slurry produced by an ice maker, a pump for pressurizing the ice slurry, a line through which the ice slurry circulates, and a cooling device into which the ice slurry flows, and the ice slurry flowing out of the cooling device is returned to the slurry tank. The invention described in claim 2 is the cooling system for computer equipment described in claim 1, which includes a coolant distribution device that controls the operation of the pump according to the amount of heat dissipated by the computer equipment. The invention described in claim 3 is a cooling system for computer equipment described in claim 1 or claim 2, wherein the cooling device is positioned in contact with or adjacent to the server chassis, or in contact with or adjacent to an electronic board within the server chassis. The invention described in claim 4 is the cooling system for computer equipment described in claim 1 or claim 2, wherein the cooling device cools a liquid refrigerant in which part or all of the computer equipment is immersed. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a cooling system for computer equipment that is easy to maintain and has high power usage efficiency. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing the configuration of a cooling system to which the present embodiment is applied; [Figure 2] 1A and 1B are diagrams illustrating the structure of a cooling device. [Figure 3] (A) is a diagram showing the external appearance of cooling devices and blade servers arranged alternately, and (B) is a diagram showing a cooling system in which cooling devices are built into blade servers. [Figure 4] FIG. 1 is a diagram showing an arrangement of cooling devices. [Figure 5] 1 is a diagram showing the configuration of a cooling system to which the present embodiment is applied; [Figure 6]1 is a diagram showing the configuration of a cooling system to which the present embodiment is applied; [Figure 7] 1A and 1B are diagrams showing examples of states of ice slurry used in a cooling system to which the present embodiment is applied. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing the configuration of a cooling system to which this embodiment is applied. The cooling system 1 shown in FIG. 1 comprises an ice slurry ice maker 10, a slurry tank 20, a slurry supply pump 30, a slurry circulation line 40, a cooling device 50, a refrigerator 58, an electromagnetic valve 60, a refrigerant return pump 70, and the like.

[0010] Ice slurry ice maker 10 produces ice slurry 53. Ice slurry 53 is produced and stored in slurry tank 20 of ice slurry ice maker 10, and is pumped by slurry supply pump 30 to circulate through slurry circulation line 40, which is a slurry circulation pipe. In other words, ice slurry 53 is always stored in slurry tank 20. Ice slurry 53 is pumped to slurry circulation line 40 by slurry supply pump 30, cools computer equipment, etc., and then returns to slurry tank 20, thereby circulating. Ice slurry ice maker 10 produces ice slurry 53 by mixing the slurry in slurry tank 20 with ice produced by cold from an ice making plate (not shown), which is in contact with a pipe through which a refrigerant such as fluorine gas circulates. The refrigerant gas is cooled by refrigerator 58. The ice slurry ice maker 10 may have the structure described in, for example, Japanese Patent Application Laid-Open No. 2022-108702 filed by the applicant. Furthermore, instead of evaporating the high-pressure refrigerant gas from the refrigerator inside the ice-making plate (evaporator) (not shown) of the ice slurry ice maker 10, liquid nitrogen may be introduced into the ice-making plate (evaporator) and evaporated therein. Using liquid nitrogen makes it possible to produce ice slurry at lower temperatures, such as -60°C or -90°C.

[0011] The cooling device 50 is a unit that directly or indirectly cools part or all of a computer device by circulating ice slurry 53 as a refrigerant. Solenoid valves 60 may be installed near the inlet and outlet of the cooling device 50 to control the injection and discharge of ice slurry 53 into the cooling device 50. The cooling device 50 cools part or all of the computer device by contacting it. Multiple cooling devices 50 can be installed in parallel for each of the computer's units. Because the heat generation amount varies depending on the load on the computer, the solenoid valves 60 can be adjusted to circulate more ice slurry 53 to units expected to generate a higher heat generation. Furthermore, instead of supplying ice slurry 53 to all of the parallel paths, the supply of ice slurry 53 can be controlled by the solenoid valves 60 installed near the inlet and outlet of the parallel paths, thereby reducing the supply of ice slurry 53 to paths expected to generate a lower heat generation. By switching between multiple parallel paths and reducing the number of circulation paths using the solenoid valves 60, the supply pump can operate at a lower pressure. Therefore, the power consumption required for driving the slurry circulation can be reduced.

[0012] Refrigerant return pump 70 pumps ice slurry 53 discharged from cooling device 50 back to ice slurry ice-making machine 10. Ice slurry 53 returned to ice slurry ice-making machine 10 as a raw material for ice slurry 53 is again produced as new ice slurry 53.

[0013] 2 is a diagram showing the structure of cooling device 50. On the back surface of cooling device 50, a serpentine aluminum pipe 51 abuts against an aluminum plate 52, and ice slurry 53 serving as a refrigerant circulates within the pipe. The refrigerant flowing through pipe 51 is preferably an ice slurry of ethanol (ethyl alcohol), and the concentration can be adjusted depending on the target cooling temperature. For example, for -20°C, the ethanol concentration is preferably 32 wt%, and for -30°C, the ethanol concentration is preferably 40 wt%. The ice slurry is a solid-liquid two-phase mixture of fine ice and liquid. Furthermore, for -40°C, the ethanol concentration is preferably 50 wt%, and for -50°C, the ethanol concentration is preferably 60 wt%.

[0014] Comparing the specific heat capacities of air, water, and liquid ethanol (20 wt% aqueous solution), which are commonly used as refrigerants, water has the highest specific heat capacity at 1.0 kJ / kg / K, 4.2 kJ / kg / K, and 3.8 kJ / kg / K, respectively. When raising the temperature of water from 1°C to 4°C, the heat absorption rate is 12.6 kJ / kg. However, when raising the temperature of a 20 wt% ethanol aqueous solution from -15°C to -12°C (17% solid), the heat absorption rate is 55.5 kJ / kg, which is higher than that of water. This indicates that the apparent specific heat is large due to the effect of the latent heat of fusion of ice, approximately four times greater than that of water, making it an excellent refrigerant for use when absorbing large amounts of heat. For this reason, ethanol ice slurry is considered an appropriate material for cooling the heat dissipation of computers, especially large computers and supercomputers. The surface of plate 52 opposite to the side on which tubes 51 are arranged may be abutted against a motherboard, a server chassis, or a blade server, for example, to cool part or all of a computer device.

[0015] Generally, when a computer's CPU temperature exceeds 80°C, its performance declines and its CPU score drops. Temperatures above 90°C or 100°C are called thermal runaway, which not only reduces performance but also increases the risk of CPU wear and breakdown if the temperature continues for a long time. For this reason, it is desirable to use a liquid refrigerant in a cooling system that can maximize heat absorption by setting it to as low a temperature as possible. However, water, an excellent refrigerant with a high specific heat, turns into ice at temperatures below 0°C, reducing its usability as a circulating refrigerant. On the other hand, the ethanol ice slurry mentioned above combines the heat absorption capacity of a refrigerant with the properties of a circulating refrigerant, making it an even better circulating refrigerant than water.

[0016] FIG. 3A is a diagram showing the external appearance of a system in which cooling devices 50 and blade servers 54 are alternately arranged. The cooling device 50 may have a structure in which a serpentine aluminum pipe 51 is sandwiched between aluminum plates 52, as in FIG. 2. The cooling device 50 does not have to be the type in which pipes through which a refrigerant (ice slurry) flows, as shown in FIG. 2. For example, the cooling device 50 may be a flat tank with two closely facing plates, four sides of which are closed and have an inlet and an outlet. In this case, the plates are maintained at a low temperature by the refrigerant flowing through the hollow interior of the flat tank. Flexible tubes 51a and 51b are connected to the inlet and outlet of the cooling device 50, respectively, for ice slurry 53. Both flexible tubes 51a and 51b are connected to the slurry circulation line 40 (see FIG. 1), and the ice slurry 53 flows into the cooling device 50 through the flexible tube 51a and flows out into the slurry circulation line 40 through the flexible tube 51b.

[0017] The blade server 54 is a removable server that is usually installed in a housing (case) that can accommodate multiple servers. The blade server 54 is a server that can be installed at a higher density than a rack mount by inserting a thin server like a blade into a housing with a unit height. The cooling devices 50 are arranged in contact with or adjacent to the blade servers 54, and cool the blade servers 54. As shown in Fig. 3(A), the cooling devices 50 and the blade servers 54 are arranged alternately in parallel, so that the blade servers 54 other than those on both ends can share the cooling devices 50 on both sides.

[0018] The solenoid valve 60a is a solenoid valve on the inlet side of the cooling device, and the solenoid valve 60b is a solenoid valve on the outlet side. The solenoid valves 60a and 60b are electrically controlled valves for adjusting the degree of opening and closing to control the flow rate of the ice slurry 53. One of the solenoid valves 60a and 60b may always be fully open, while only the opening and closing of the other may be controlled.

[0019] Although the computer system consisting of multiple blade servers 54 is not shown in FIG. 3, the control management unit of the coolant distribution device constantly monitors which blade servers 54 are under processing load, and can estimate the amount of heat dissipation from the processing load. Therefore, the control management unit can adjust the amount of ice slurry 53 supplied to each blade server 54 according to the estimated amount of heat dissipation of each of the multiple blade servers 54. The control management unit can control solenoid valves 60a and / or 60b based on the estimated amount of heat dissipation of the blade servers 54. Alternatively, the control management unit can control the amount of ice slurry supplied by controlling slurry supply pump 30 in FIG. 1.

[0020] 3(B) is a diagram showing a cooling system in which a cooling device 50 (not shown) is built into a blade server 54. The cooling device 50 is disposed in contact with or adjacent to a CPU (Central Processing Unit) or MCU (Micro Controller Unit) inside the housing of the blade server 54, or a motherboard on which they are mounted. In the example of FIG. 3(B), the cooling efficiency is increased because the heat-dissipating main body such as the CPU or MCU can be directly cooled.

[0021] 4 is a diagram showing the arrangement of cooling devices 50. Server chassis 55 are arranged side by side horizontally, and each server chassis 55 has a motherboard 56 and a cooling device 50 built in. The cooling devices 50 are arranged so as to abut or be adjacent to the motherboard 56 built in the server chassis 55. Ice slurry 53 (see FIG. 1) is supplied to the cooling devices 50 in the multiple server chassis 55 via pipe 51a branching from the slurry circulation line 40. After absorbing the heat dissipated from the server chassis 55 and completing its cooling, the ice slurry 53 returns to the slurry circulation line 40 via pipe 51b.

[0022] Although not shown in FIG. 4, in a computer system consisting of multiple server chassis 55, the control management unit of the coolant distribution device constantly monitors which servers are under processing load, and can estimate the amount of heat dissipation from the processing load. Therefore, the control management unit can adjust the amount of ice slurry 53 supplied to each server chassis 55 according to the estimated amount of heat dissipation of each of the multiple server chassis 55. Although not shown in FIG. 4, the control management unit can control the solenoid valve located between the slurry circulation line 40 and the cooling device 50 based on the estimated amount of heat dissipation of the server chassis 55. Alternatively, the control management unit can control the amount of ice slurry supplied by controlling the slurry supply pump 30 of FIG. 1.

[0023] 5 is a diagram showing the configuration of a cooling system 1 to which this embodiment is applied. A multi-tiered rack is provided with a management unit 61, an ice slurry distributor 62, a slurry supply pump 30, server chassis 56a to 56e, an inlet 100 through which ice slurry 53 flows in from a slurry circulation line 40 (not shown), and an outlet 110 through which ice slurry 53 flows out to the slurry circulation line 40. The management unit 61 estimates the amount of heat radiation from the load status of the processors in each server chassis that constitutes the computer system, and calculates how much ice slurry 53 (see FIG. 1) should be supplied to each of the server chassis 56a to 56e. The ice slurry distribution device 62 controls the amount of ice slurry 53 supplied to the cooling devices 50a to 50e by operating the slurry supply pump 30 and adjusting solenoid valves (not shown) to supply the estimated amount of ice slurry 53 that should be supplied to each server chassis 56a to 56e. The cooling devices 50a to 50e are units that directly or indirectly cool some or all of the computer equipment in the server chassis 56a to 56e by circulating the refrigerant of ice slurry 53 inside.

[0024] 5 shows inlet 100 through which ice slurry 53 flows from slurry circulation line 40 (see FIG. 1) into the rack and outlet 110 through which ice slurry 53 flows from the rack into slurry circulation line 40, but the present invention is not limited to this configuration. An ice maker and a slurry tank may be incorporated into the rack as part of ice slurry distributor 62, and ice slurry distributor 62 may control the amount of ice slurry 53 produced by the ice slurry ice maker together with slurry supply pump 30 and a solenoid valve.

[0025] FIG. 6 is a diagram showing the configuration of a cooling system to which this embodiment is applied. Servers 300 in a data center 200 are immersed in an immersion tank 500 filled with a liquid coolant. The liquid coolant is an inert liquid, such as a fluorocarbon-based coolant, and is preferably a liquid that does not evaporate easily. The immersion-type liquid cooling medium is pumped by a fluid pump 700, circulates through a supply line 400, passes through a return line 600, and is cooled in a heat exchanger 800 before circulating. A liquid distribution unit (CDU controller) 900 controls the operation of the fluid pump 700 according to the load processed by the server. Furthermore, the liquid coolant used for immersion is cooled in a cooling device 50 (not shown) disposed within the heat exchanger 800. The cooling device 50 is a device that exerts a cooling effect by circulating ice slurry 53, as in the configurations described with reference to Figures 1 to 5. In the example embodiments of Figures 1 to 5, the cooling device 50 cooled the computer equipment itself, but in the embodiment shown in Figure 6, the cooling device 50 cools the liquid cooling medium for immersion.

[0026] The state of the ice slurry 53 in the cooling device can be adjusted depending on the temperature and type of liquid refrigerant used for immersion. Figure 7 shows an example of the state of ice slurry 53 used in a cooling system to which this embodiment is applied. Ice slurry 53 is produced from raw materials such as ethanol and salt water, and is a fluid consisting of fine ice and liquid. It is a refrigerant in a state that can flow through piping when pressure-fed by a pump. By selecting the type of raw material and changing the ratio of ice to liquid, the temperature, flow state, viscosity, etc. of the refrigerant can be changed. [Explanation of symbols]

[0027] 1...Cooling system, 10...Ice slurry ice maker, 20...Slurry tank, 30...Slurry supply pump, 40...Slurry circulation line, 50...Cooling device, 51...Tube, 52...Plate, 53...Ice slurry, 54...Blade server, 55...Server chassis, 56...Motherboard, 58...Refrigerator, 60...Solenoid valve, 70...Refrigerant return pump, 200...Data center, server...300, Supply line...400, Immersion tank...500, Return line...600, Fluid pump...700, Heat exchanger...800, Liquid distribution unit...900

Claims

1. a slurry tank for storing ice slurry produced by the ice maker; a pump for pumping the ice slurry; a line through which the ice slurry circulates; a cooling device into which the ice slurry flows; A cooling system for computer equipment, wherein the ice slurry flowing out of the cooling device is returned to the slurry tank.

2. 2. The cooling system for computer equipment according to claim 1, further comprising a coolant distribution device that controls operation of said pump in accordance with the amount of heat dissipated by said computer equipment.

3. 3. The cooling system for computer equipment according to claim 1, wherein the cooling device is disposed in contact with or adjacent to a server chassis, or in contact with or adjacent to an electronic board within the server chassis.

4. 3. The cooling system for computer equipment according to claim 1, wherein the cooling device cools a liquid coolant that immerses part or all of the computer equipment.

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