LIQUID IMMERSION COOLING DEVICE

Abstract

A liquid immersion cooling device cools a heating element provided on a circuit board and comprises: a housing configured to accommodate the circuit board therein and store a refrigerant in an inner lower region; a cover configured to surround at least the heating element and having an opening region in at least a part of the cover; a condensing region provided above a liquid level of the refrigerant in the housing and configured to condense the evaporated refrigerant; a refrigerant receiving region provided above the liquid level and below the condensing region and configured to receive the refrigerant in a liquid phase condensed by the condensing region;and a refrigerant introduction flow channel configured to guide the refrigerant received from the refrigerant receiving area into the cover;

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a liquid immersion cooling device.

[0002] Priority is claimed for Japanese Patent Application No. 2022-134839, filed on August 26, 2022, the contents of which are hereby incorporated by reference. STATE OF THE ART

[0003] Patent Document 1 discloses a method for recovering a refrigerant used for liquid immersion cooling. In this refrigerant recovery method, the refrigerant is distilled in a distillation tank to separate a low-volatility impurity. The evaporated refrigerant is recovered in a circulation tank. Citation listPatent document

[0004] Patent Document 1: US Patent No. 10773192 SUMMARY OF THE INVENTIONTechnical Problem

[0005] However, the refrigerant recovery method described in Patent Document 1 requires a large device such as the distillation tank. Therefore, the entire device becomes very large. Furthermore, a heater is used for refrigerant distillation. Therefore, another problem is that power consumption increases.

[0006] The present disclosure has been made to solve the problems described above, and an object of the present disclosure is to provide a liquid immersion refrigerator that can reduce power consumption while achieving size reduction. Solution to the problem

[0007] To achieve the above-described object, the present disclosure provides a liquid immersion cooling device that cools a heating element provided on a circuit board, the immersion cooling device comprising: a housing configured to accommodate the circuit board inside and store a refrigerant in an inner lower region; a cover configured to surround at least the heating element and having an opening region in at least a part of the cover; a condensing region provided above a liquid level of the refrigerant in the housing and configured to condense the evaporated refrigerant; a refrigerant receiving region provided above the liquid level and below the condensing region and configured to receive the refrigerant in a liquid phase condensed by the condensing region;and a refrigerant introduction flow channel configured to guide the refrigerant received from the refrigerant receiving area into the cover; Advantageous effects of the invention

[0008] With the liquid immersion cooling device according to the present disclosure, it is possible to reduce power consumption while reducing the size. BRIEF DESCRIPTION OF THE DRAWINGS [ Fig. 1] A schematic view showing the configuration of a liquid immersion cooling device according to a first embodiment of the present disclosure. [ Fig. 2] A schematic view showing the configuration of a liquid immersion cooling device according to a second embodiment of the present disclosure. [ Fig. 3] A schematic view showing the configuration of a lid portion according to the second embodiment of the present disclosure. [ Fig. 4] A schematic view showing the configuration of a liquid immersion cooling device according to a third embodiment of the present disclosure. [ Fig. 5] A schematic view showing the configuration of a liquid immersion cooling device according to a fourth embodiment of the present disclosure. [ Fig. 6] A schematic view showing the configuration of a liquid immersion cooling device according to a fifth embodiment of the present disclosure. DESCRIPTION OF THE EMBODIMENTS<Erste Ausführungsform> (liquid immersion cooling device)

[0009] Hereinafter, a liquid immersion cooling device 10 according to a first embodiment of the present disclosure will be described with reference to Fig. 1 described.

[0010] As in Fig. As shown in Figure 1, the liquid immersion cooling device 10 is used for cooling an electronic device. In the present embodiment, the liquid immersion cooling device 10 is used in a server 1 that performs high-speed computing.

[0011] Server 1 contains a printed circuit board and an electronic component, such as a CPU or GPU chip, located on the printed circuit board. Because the CPU or GPU is a component responsible for high-speed computing, it experiences a high load. Therefore, the CPU or GPU generates heat at a higher temperature than other areas of Server 1.

[0012] In the following, the printed circuit board of server 1 is simply referred to as “board 2” and the chip, e.g. the CPU or GPU, is referred to as “heating element 3”.

[0013] The circuit board 2 is formed in a rectangular plate shape. The circuit board 2 is arranged vertically and extends in an up-down direction.

[0014] The heating element 3 is installed so that it can be attached to a surface of the circuit board 2. Therefore, in the present embodiment, the heating element 3 is arranged vertically and extends in the up-down direction, similar to the circuit board 2. The heating element 3 includes a heating element body 4 and a cooling plate 5 made of metal and tightly connected to the heating element body 4. The cooling plate 5 is provided to radiate the heat from the heating element body 4.

[0015] In addition to the CPU and GPU, the heating element 3 includes all heating elements that generate heat on the circuit board 2. Furthermore, the cooling plate 5 does not need to be included in the heating element 3.

[0016] The heating element 3 is powered by a power supply 6 outside the server 1. The power supply 6 is connected to the circuit board 2 via a power supply cable 7. The heating element 3 is electrically connected to the power supply 6 via the power supply cable 7 and the circuit board 2. Furthermore, the circuit board 2 is connected to an external device (not shown) via a communication cable 8. The communication cable 8 is, for example, a LAN cable. The server 1 communicates with the external device via the communication cable 8. (Liquid immersion cooling device configuration)

[0017] A configuration of the liquid immersion cooling device 10 is described below.

[0018] The liquid immersion cooling device 10 is a device that cools the heating element 3 by causing a liquid-phase refrigerant R and the heating element 3 to perform heat exchange with each other in a state where the heating element 3 is immersed in the liquid-phase refrigerant R. The refrigerant R used in the liquid immersion cooling device 10 is an insulating liquid.

[0019] As in Fig. 1, the liquid immersion cooling device 10 includes a housing 20, a cover 30, a heat sink 11, a condensing region 40, a refrigerant receiving region 50, and a refrigerant introduction flow channel 60. Fig. 1 shows a state in which the server 1 is operating and the heating element 3 generates heat. (Housing)

[0020] The casing 20 accommodates the circuit board 2 inside. The liquid-phase refrigerant R is stored in an inner lower portion of the casing 20. In the present embodiment, the entire circuit board 2 is immersed in the liquid-phase refrigerant R stored in the casing 20. In the present embodiment, a case where the casing 20 includes a lower portion casing 21, an upper portion casing 22, and a connecting wall 23 will be described as an example.

[0021] The lower section casing 21 is a bottomed container with an upward opening. The lower section casing 21 is a portion of the casing 20 in which the refrigerant R is stored in the liquid phase. The upper section casing 22 is arranged above the lower section casing 21. The upper section casing 22 is a bottomed container with an downward opening. In the present embodiment, the opening area of ​​the upper section casing 22 is larger than the opening area of ​​the lower section casing 21. The connecting wall 23 is formed to protrude outward from an opening of the lower section casing 21 in the horizontal direction. The connecting wall 23 connects the opening of the lower section casing 21 and an opening of the upper section casing 22.

[0022] A closed space is formed by the lower section housing 21, the upper section housing 22, and the connecting wall 23. The space in the housing 20 accommodates not only the circuit board 2 but also the power supply 6, the power supply cable 7, and the communication cable 8. The circuit board 2 is arranged in the lower section housing 21. The circuit board 2 is installed in a position floating upward from a lower section of the lower section housing 21. The power supply 6 is attached to the connecting wall 23.

[0023] In the casing 20, in addition to the liquid-phase refrigerant R stored in the sub-section casing 21, there is also the gas-phase refrigerant R. The gas-phase refrigerant R is condensed at the power supply 6 or the power supply cable 7 and then converted into the liquid phase. In addition, since a plasticizer is contained in the coating or the like of a cable within the power supply 6, the power supply cable 7, and the communication cable 8, the plasticizer can be dissolved in the refrigerant R. The refrigerant R in which the plasticizer is dissolved is mixed with the refrigerant R stored in the casing 20 from the cable within the power supply 6, the power supply cable 7, and the communication cable 8. (Cover)

[0024] The cover 30 is housed inside the housing 20. The cover 30 is attached to the surface of the circuit board 2. The cover 30 is a member that surrounds at least the heating element 3. In the present embodiment, the entire cover 30 is immersed in the refrigerant R stored in the housing 20. The cover 30 has an opening portion 31 in at least a partial portion. The opening portion 31 is provided above the heating element 3. The opening portion 31 is open at the top. (heat sink)

[0025] The heat sink 11 (heat sink) is arranged in the cover 30. The heat sink 11 is fixed to the cooling plate 5 of the heating element 3. The heat sink 11 is thermally connected to the heating element 3. The heat sink 11 has a structure for increasing the surface area of ​​the heating element 3 and assisting in cooling the heating element 3. In the present embodiment, the heat sink 11 is provided separately from the cover 30. (Condensation area)

[0026] The condenser region 40 is arranged above a liquid level of the refrigerant R in the housing 20. The condensation region 40 condenses the evaporated refrigerant R in the housing 20. The condensation region 40 is attached to the upper region housing 22.

[0027] The condenser section 40 according to the present embodiment is a water-cooled condenser. The condensing section 40 includes a plurality of heat transfer tubes 41. Cooling water W flows through the heat transfer tube 41. The refrigerant receiving section 50 is arranged below the condensing section 40. (Refrigerant receiving area)

[0028] The refrigerant receiving area 50 is located above the liquid level of the refrigerant R stored in the housing 20. The refrigerant receiving area 50 receives the refrigerant R in the liquid phase condensed by the condensation area 40. The refrigerant receiving area 50 has a receiving area body 51 and a discharge pipe 52.

[0029] The receiving area body 51 is an upwardly open container. The receiving area body 51 has a bottom wall 53 and side walls 54. The bottom wall 53 extends horizontally. An outer peripheral edge of the bottom wall 53 is located outside the condensation area 40 in the up-down direction. The bottom wall 53 is provided with a discharge hole 55 penetrating the bottom wall 53. The bottom wall 53 is oriented obliquely downward toward the discharge hole 55. The side walls 54 extend upward from the outer peripheral edge of the bottom wall 53.

[0030] The discharge pipe 52 is connected to the discharge hole 55 of the receiving section body 51. The discharge pipe 52 extends downward from the receiving section body 51. The discharge pipe 52 is provided so as to approach the connecting wall 23 of the casing 20 toward the bottom. The refrigerant introduction flow channel 60 is provided below a lower end of the discharge pipe 52. (Refrigerant introduction flow channel)

[0031] The refrigerant introduction flow channel 60 is a flow channel that guides the refrigerant R received from the refrigerant receiving area 50 into the cover 30. The refrigerant introduction flow channel 60 includes a storage tank 61 and a refrigerant supply pipe 62. (Storage tank)

[0032] The storage tank 61 is located directly below the lower end of the discharge pipe 52. The storage tank 61 is an upwardly open container. The refrigerant R received by the refrigerant receiving section 50 is supplied from the discharge pipe 52 to the storage tank 61. The storage tank 61 stores the refrigerant R received by the refrigerant receiving section 50. In the present embodiment, the storage tank 61 is provided on the connection wall 23 of the housing 20. The storage tank 61 is located above the liquid level of the refrigerant R stored in the housing 20. The refrigerant supply pipe 62 is arranged in a lower region of the storage tank 61. (refrigerant supply pipe)

[0033] The refrigerant supply pipe 62 connects the storage tank 61 and the cover 30. The refrigerant supply pipe 62 communicates with the storage tank 61 and the cover 30. Through the refrigerant supply pipe 62, the refrigerant R flows from the storage tank 61 toward the cover 30. In the present embodiment, one end of the refrigerant supply pipe 62 is connected to the lower portion of the storage tank 61. The other end of the refrigerant supply pipe 62 is connected to a lower portion of the cover 30. Furthermore, the other end of the refrigerant supply pipe 62 is located below the heating element 3. In the present embodiment, the refrigerant supply pipe 62 is immersed in the refrigerant R stored in the case 20. (Circulation of the refrigerant)

[0034] Next, the circulation of the refrigerant R in the immersion cooler 10 is described.

[0035] When the server 1 starts operating, a load is applied to the heating element 3, and the heating element 3 generates heat. Then, heat exchange occurs between the heating element 3 and the refrigerant R in the cover 30. As a result, the heating element 3 is cooled. On the other hand, the refrigerant R in the cover 30 is heated. This creates an upward flow in the cover 30. Due to the upward flow, the refrigerant R is discharged from the cover 30 to the outside.

[0036] In the present embodiment, the liquid immersion cooling device 10 cools the heating element 3 by a two-phase cooling method. That is, the liquid immersion cooling device 10 cools the heating element 3 by evaporating the refrigerant R around the heating element 3 to remove the latent heat of evaporation of the refrigerant R from the heating element 3. As a result, the refrigerant R in the cover 30 is boiled, and a part of the refrigerant R in the cover 30 evaporates to form the gas phase.

[0037] The refrigerant R boiling and evaporating in the cover 30 and the refrigerant R evaporating from the liquid level of the refrigerant R in the housing 20 are supplied to the condensation area 40. The evaporated refrigerant R exchanges heat with the cooling water W flowing through the condensation area 40. As a result, the refrigerant R is condensed and converted from the gas phase to the liquid phase. The refrigerant R condensed in the condensation area 40 is recovered by the refrigerant receiving area 50.

[0038] The refrigerant R is then fed from the refrigerant receiving area 50 to the storage tank 61. The refrigerant R is temporarily stored in the storage tank 61.

[0039] The refrigerant R is separated from impurities such as a non-volatile oil component by evaporation. Therefore, the evaporated refrigerant R is a clean refrigerant R with few impurities, compared with the refrigerant R from which the plasticizer is extracted by connecting to the power supply 6 or the power supply cable 7, or the refrigerant R stored in the housing 20. The storage tank 61 stores the refrigerant R obtained by condensing the evaporated refrigerant R. The storage tank 61 therefore stores the clean refrigerant R with few impurities.

[0040] The refrigerant R stored in the storage tank 61 is sucked upward into the cover 30 through the refrigerant supply pipe 62 due to the flow generated by the heat generation of the heating element 3. As a result, clean refrigerant R is always supplied to the cover 30 during the heat generation of the heating element 3. The refrigerant R supplied to the cover 30 is discharged back to the outside of the cover 30 after the heat exchange with the heating element 3. In this way, the refrigerant R circulates in the cooling device. (Operation and effects)

[0041] With the liquid immersion cooling device 10 according to the present embodiment, the following operation and effects are observed.

[0042] In the present embodiment, the liquid immersion cooling device 10 includes the housing 20, the cover 30, the condensing region 40, the refrigerant receiving region 50, and the refrigerant introduction channel 60. The circuit board 2 is housed in the housing 20. The refrigerant R is stored in the inner lower region of the housing 20. The cover 30 surrounds at least the heating element 3. The cover 30 has an opening region 31 in at least a partial region. The condensing region 40 is arranged above a liquid level of the refrigerant R in the housing 20. The condensing region 40 condenses the evaporated refrigerant R. The refrigerant receiving region 50 is arranged above the liquid level of the refrigerant R in the housing 20 and below the condensing region 40. The refrigerant receiving region 50 receives the refrigerant R in the liquid phase condensed by the condensing region 40.The refrigerant introduction flow channel 60 guides the refrigerant R received from the refrigerant receiving area 50 into the cover 30.

[0043] In the present embodiment, the gas-phase refrigerant R is condensed in the casing 20 by the condensation section 40 and then converted into the liquid phase. The liquid-phase refrigerant R is introduced into the cover 30 through the refrigerant receiving section 50 and the refrigerant introduction flow channel 60. The gas-phase condensed refrigerant R does not contain impurities such as a non-volatile oil component. Therefore, the refrigerant R introduced into the cover 30 is a clean refrigerant R with few impurities.

[0044] In addition, the refrigerant R in the cover 30 is heated by the heating element 3. This generates an upward flow in the cover 30. Due to the upward flow, the clean refrigerant R is sucked into the refrigerant introduction flow channel 60 in the cover 30. As a result, the clean refrigerant R is always supplied to the heating element 3 while the heating element 3 generates heat.

[0045] As described above, according to the present embodiment, it is possible to supply the clean refrigerant R with few impurities to the heating element 3 without providing a large device such as a distillation tank. Therefore, the liquid immersion cooling device 10 can be reduced in size. Furthermore, a heater for distilling the refrigerant R is not required. Since the refrigerant R is circulated by the upward flow generated by the heat generation of the heating element 3, a motor for circulating the refrigerant R is also not required. Therefore, the power consumption of the liquid immersion cooling device 10 can be reduced.

[0046] In the present embodiment, the opening portion 31 is arranged above the heating element 3.

[0047] As a result, the refrigerant R in the cover 30 is likely to flow out of the cover 30 through the opening portion 31 due to the upward flow generated by the heating element 3. Therefore, the clean refrigerant R is smoothly supplied to the heating element 3. Therefore, the precipitation and accumulation of impurities such as oil components in the heating element 3 and the heat sink 11 are suppressed. Therefore, the decrease in the cooling performance of the liquid immersion cooler 10 is suppressed.

[0048] In the present embodiment, the storage tank 61 is located above the liquid level of the refrigerant R stored in the housing 20.

[0049] As a result, the liquid level of the refrigerant R in the storage tank 61 is higher than the liquid level of the refrigerant in the housing 20. Therefore, pressure is generated in the refrigerant introduction flow channel 60, which causes the refrigerant R to flow from the storage tank 61 toward the cover 30. Therefore, the liquid immersion cooling device 10 can circulate the refrigerant R more evenly.

[0050] In the present embodiment, the liquid immersion cooling device 10 comprises a heat sink 11 which is thermally connected to the heating element 3.

[0051] This increases a contact area between the heating element 3 and the refrigerant R. Therefore, the cooling efficiency of the liquid immersion cooling device 10 can be improved.

[0052] In the present embodiment, the other end of the refrigerant supply pipe 62 is connected to the cover 30 below the heating element 3.

[0053] As a result, the clean refrigerant R is directly supplied to the cooling plate 5 of the heating element 3. Therefore, the precipitation and accumulation of impurities such as oil components in the heating element 3 and the heat sink 11 are suppressed. Therefore, the decrease in the cooling performance of the liquid immersion cooler 10 is suppressed. Furthermore, even in a case where the oil component is bound to the heating element 3 and the heat sink 11, the liquid immersion cooler 10 can dissolve the bound oil component in the clean refrigerant R to remove the oil component.

[0054] In the first embodiment, the storage tank 61 is located above the liquid level of the refrigerant R stored in the housing 20. However, the present disclosure is not limited thereto. For example, the storage tank 61 may be arranged at a lower position than the liquid level of the refrigerant R stored in the housing 20.

[0055] In the first embodiment, the liquid immersion cooling device 10 cools the heating element 3 using a two-phase cooling method, but the present disclosure is not limited thereto. The liquid immersion cooling device 10 may cool the heating element 3 using a single-phase cooling method. In this case, the refrigerant R heated by the heating element 3 in the cover 30 flows out of the cover 30 in a liquid state.

[0056] In the first embodiment, the casing 20 includes the lower section casing 21, the upper section casing 22, and the connecting wall 23, and the opening area of ​​the upper section casing 22 is larger than the opening area of ​​the lower section casing 21, but the present disclosure is not limited thereto. For example, the opening area of ​​the upper section casing 22 may be smaller than the opening area of ​​the lower section casing 21. Furthermore, the casing 20 may be, for example, a cubic container that does not have the connecting wall 23. In addition, the storage tank 61 and the discharge pipe 52 may be omitted, the receiving section body 51 may temporarily store the refrigerant R instead of the storage tank 61, and the refrigerant supply pipe 62 may be connected to the supply hole 55 of the receiving section body 51.The refrigerant R is supplied directly from the receiving area 51 to the refrigerant supply pipe 62 by connecting the refrigerant supply pipe 62 to the discharge hole 55. <Zweite Ausführungsform>

[0057] Hereinafter, a liquid immersion cooling device 210 according to a second embodiment of the present disclosure will be described with reference to the Fig. 2 and Fig. 3. For the same configuration as the configuration of the first embodiment, the same names and the same reference numbers are used, and a description thereof is omitted accordingly.

[0058] As in Fig. 2, the liquid immersion cooling device 210 includes a lid portion 70 and a flow rate adjustment portion 9. Fig. 2 shows a state in which the server 1 is stopped and the heating element 3 does not generate heat. (lid area)

[0059] The lid portion 70 is provided at the opening portion 31 of the cover 30. The lid portion 70 opens and closes the opening portion 31. In the following drawings, a state in which the lid portion 70 closes the opening portion 31 is represented by a solid line, and a state in which the lid portion 70 opens the opening portion 31 is represented by a two-dashed chain line. As shown in Fig. 3, the lid portion 70 includes a lid portion body 71 and a check valve structure 72. (cover area body)

[0060] The lid portion body 71 is formed in the shape of a plate which is larger than the opening portion 31. When the pressure of the refrigerant R flowing from the inside of the cover 30 toward the opening portion 31 is lower than a predetermined value, the lid portion body 71 covers the entire opening portion 31 of the cover 30. (Check valve structure)

[0061] The check valve structure 72 pushes the lid portion body 71 upward by the pressure of the refrigerant R to open the opening portion 31 in a case where the pressure of the refrigerant R flowing out of the cover 30 is equal to or greater than the predetermined value. The check valve structure 72 according to the present embodiment is a swing type. The check valve structure 72 includes a hinge 73 and an arm 74. The hinge 73 is arranged near the opening portion 31 of the cover 30. One end of the arm 74 is connected to the hinge 73. The other end of the arm 74 is connected to the lid portion body 71.When the pressure of the refrigerant R flowing from the inside of the cover 30 toward the opening portion 31 is equal to or greater than the predetermined value, the lid portion body 71 is pushed upward by the flow of the refrigerant R toward the outside of the cover 30, and thus the opening portion 31 of the cover 30 is opened. The arm 74 rotates around the hinge 73 due to the upward flow generated by the heat generation of the heating element 3.

[0062] A rotation angle of the arm 74 is set to be equal to or less than 90 degrees around the hinge 73. Therefore, when the pressure of the refrigerant R flowing from the inside of the cover 30 to the opening portion 31 is lower than the predetermined value, the arm 74 and the lid portion body 71 are rotated around the hinge 73 by the self-weight of the arm 74 and the lid portion body 71, and the lid portion body 71 closes the opening portion 31 of the cover 30 again.

[0063] The check valve structure 72 may be provided with a spring that generates an elastic force in a direction in which the lid portion body 71 is pressed against the opening portion 31 of the cover 30. (Flow rate adjustment range)

[0064] The flow rate adjustment section 9 includes a circulation pump 12 that pumps the refrigerant R from the refrigerant introduction flow channel 60 into the cover 30. The flow rate adjustment section 9 adjusts the flow rate by the circulation pump 12 so that the refrigerant R is temporarily stored on the upstream side in the refrigerant introduction flow channel of the refrigerator 60. In the present embodiment, a case where the flow rate adjustment section 9 includes a circulation pump 12 and a flow rate adjustment valve 13 will be described as an example. (circulation pump)

[0065] The circulation pump 12 is provided in the refrigerant supply pipe 62 of the refrigerant introduction flow channel 60. The circulation pump 12 pumps the refrigerant R from the storage tank 61 into the cover 30. (Flow rate adjustment valve)

[0066] The flow rate adjustment valve 13 is provided in the refrigerant supply pipe 62 of the refrigerant introduction flow channel 60. The flow rate adjustment valve 13 is arranged on the cover 30 side with respect to the circulation pump 12. That is, the flow rate adjustment valve 13 is provided on the downstream side in the refrigerant supply pipe 62 in the flow direction of the refrigerant R to the circulation pump 12. The flow rate adjustment valve 13 opens and closes the refrigerant supply pipe 62. Furthermore, the valve 13 adjusts the opening degree of the refrigerant supply pipe 62 to regulate the flow rate of the refrigerant R in the refrigerant supply pipe 62. (Operation and effects)

[0067] The liquid immersion cooling device 210 according to the present embodiment has the following operation and effects.

[0068] In the present embodiment, the liquid immersion cooling device 210 further includes the flow rate adjustment section 9 including the circulation pump 12 that pumps the refrigerant R in the refrigerant introduction flow channel 60 into the cover 30 and adjusts the flow rate via the circulation pump 12 and temporarily stores the refrigerant R upstream in the refrigerant introduction flow channel 60.

[0069] Consequently, the liquid immersion cooler 210 can temporarily store the clean refrigerant R upstream in the refrigerant introduction flow channel 60, adjust the flow rate of the clean refrigerant R supplied to the heating element 3 by the circulation pump 12 via the flow rate adjustment section 9, and adjust the amount of the clean refrigerant R supplied to the heating element 3 and the timing of supplying the clean refrigerant R to the heating element 3. In the present embodiment, the flow rate adjustment section 9 includes the circulation pump 12 and the flow rate adjustment valve 13, and the circulation pump 12 is provided in the refrigerant supply pipe 62 and pumps the refrigerant R in the storage tank 61 into the cover 30. The flow rate adjustment valve 13 adjusts the flow rate of the refrigerant R in the refrigerant supply pipe 62.The clean refrigerant R is temporarily stored in the storage tank 61, and the amount of the clean refrigerant R supplied to the heating element 3 and the timing of supplying the clean refrigerant R to the heating element 3 can be adjusted by the circulation pump 12 and the flow rate adjustment valve 13. Therefore, for example, before the operation of the server 1 is stopped, the liquid immersion cooling device 210 can reduce the supply amount of the refrigerant R supplied into the cover 30 and store the clean refrigerant R in the storage tank 61. Accordingly, the liquid immersion cooling device 210 can supply the refrigerant R to the heating element 3 by supplying the refrigerant R in the storage tank 61 to the inside of the cover 30 after the operation of the server 1 is stopped. This suppresses the precipitation and accumulation of impurities such as the oil component in the heating element 3 and the heat sink 11.Therefore, the decrease in the cooling performance of the liquid immersion cooling device 210 is suppressed.

[0070] In the present embodiment, the liquid immersion cooling device 210 includes the lid portion 70 that opens and closes the opening portion 31.

[0071] Accordingly, the liquid immersion cooling device 210 can close the opening portion 31 of the cover 30 and store the clean refrigerant R in the cover 30 when the heating element 3 does not generate heat, for example, when the operation of the server 1 is stopped. Therefore, the liquid immersion cooling device 210 can fill the interior of the cover 30 with the clean refrigerant R even when the heating element 3 does not generate heat. Therefore, the precipitation and accumulation of impurities such as the oil component in the heating element 3 and the heat sink 11 are suppressed. Therefore, the decrease in the cooling performance of the liquid immersion cooling device 210 is suppressed.

[0072] In the present embodiment, the lid portion 70 has the check valve structure 72 that opens the opening portion 31 when the pressure of the refrigerant R flowing out of the cover 30 is equal to or greater than the predetermined value.

[0073] Accordingly, the liquid immersion cooling device 210 can suppress the backflow of the refrigerant R into the cover 30 through the check valve structure 72. Therefore, the liquid immersion cooling device 210 can suppress the inflow of the contaminated refrigerant R containing a large amount of impurities stored in the casing 20 into the cover 30. Therefore, the precipitation and accumulation of impurities such as the oil component in the heating element 3 and the heat sink 11 are suppressed. Therefore, the decrease in the cooling performance of the liquid immersion cooling device 210 is suppressed.

[0074] In the second embodiment, the check valve structure 72 of the lid portion 70 is a swing type, but the present disclosure is not limited thereto. For example, the check valve structure 72 of the lid portion 70 may be a lift type.

[0075] In the second embodiment, the flow rate adjustment section 9 includes the circulation pump 12 and the flow rate adjustment valve 13, but the present disclosure is not limited thereto. For example, the flow rate adjustment section 9 may not include the flow rate adjustment valve 13 and a control device (not shown), and the flow rate of the refrigerant R through the circulation pump 12 may be adjusted by controlling the rotational speed of the circulation pump 12 via the control device.

[0076] Furthermore, the flow rate adjustment section 9 can also be applied, for example, in a case where the storage tank 61 and the discharge pipe 52 are not provided, and the refrigerant supply pipe 62 is connected to the discharge hole 55 of the receiving section body 51. In this case, the liquid immersion cooling device 210 introduces the refrigerant R temporarily stored in the receiving section body 51 into the cover 30 while adjusting the flow rate and timing via the flow rate adjustment section 9. <Dritte Ausführungsform>

[0077] Hereinafter, a liquid immersion cooling device 310 according to a third embodiment of the present disclosure will be described with reference to Fig. 4. For the same configuration as the configuration of the first embodiment, the same names and the same reference numerals are used, and a description thereof is omitted accordingly.

[0078] As in Fig. 4, the cover 330 protrudes beyond an upper edge of the circuit board 2. Fig. 4 shows a state in which the server 1 is operating and the heating element 3 generates heat.

[0079] An opening portion 331 of the cover 330 is provided at a height equal to or higher than the liquid level of the refrigerant R stored in the housing 20. In the present embodiment, the opening portion 331 of the cover 330 is provided at a height equal to or higher than the connecting wall 23 of the housing 20. The cover 330 and the circuit board 2 are completely sealed with an epoxy resin or the like. (Operation and effects)

[0080] With the liquid immersion cooling device 310 according to the present embodiment, the following operation and effects are observed.

[0081] In the present embodiment, the opening portion 331 is provided at a height equal to or higher than the liquid level of the refrigerant R stored in the case 20.

[0082] As a result, the liquid immersion cooling device 310 can suppress the inflow of the refrigerant R containing the impurities stored in the casing 20 into the cover 330 through the opening portion 331. Therefore, the liquid immersion cooling device 310 can prevent the mixing of the clean refrigerant R in the cover 330 and the contaminated refrigerant R containing a large amount of impurities in the casing 20. Therefore, the precipitation and accumulation of impurities such as oil components in the heating element 3 and the heat sink 11 are suppressed. Therefore, the decrease in the cooling performance of the liquid immersion cooling device 310 is suppressed. <Vierte Ausführungsform>

[0083] Hereinafter, a liquid immersion cooling device 410 according to a fourth embodiment of the present disclosure will be described with reference to Fig. 5. For the same configuration as the configurations of the first embodiment and other embodiments, the same names and the same reference numerals are used, and a description thereof is omitted accordingly.

[0084] As in Fig. As shown in Fig. 5, the flow rate adjustment portion 9, which includes the circulation pump 12 and the flow rate adjustment valve 13, is provided in the refrigerant supply pipe 62. Moreover, as in the third embodiment, the opening portion 331 of the cover 330 is provided at a height equal to or higher than the liquid level of the refrigerant R stored in the case 20. Fig. 5 shows a state in which the server 1 is operating and the heating element 3 generates heat.

[0085] The cover 330 and the circuit board 2 are completely sealed with an epoxy resin or similar material. The cover 330 is located above the liquid level of the refrigerant R stored in the housing 20.

[0086] Furthermore, the heat sink 11 is coated with an oil-repellent coating. The oil-repellent coating of the heat sink 11 is preferably a fluorine-based coating. It should be noted that in a case where the refrigerant R is a fluorine-containing refrigerant, the material for the oil-repellent coating must be resistant to the fluorine-containing refrigerant.

[0087] Furthermore, the immersion cooling device 410 comprises an inclined plate 18, a refrigerant return channel 14, a return pump 15, a return flow adjustment valve 16 and a filter 17. (Slanted plate)

[0088] The inclined plate 18 is attached to the inner lower portion of the housing 20. The inclined plate 18 extends horizontally. The inclined plate 18 is gradually inclined so that it is disposed downward toward the side wall of the housing 20 on the storage tank 61 side. (refrigerant return channel)

[0089] The refrigerant return passage 14 guides the refrigerant R stored in the casing 20 to the refrigerant introduction flow passage 60. The refrigerant return passage 14 is disposed outside the casing 20. One end of the refrigerant return passage 14 is connected to a position corresponding to a lower end of the inclined plate 18 in the lower portion of the casing 20. One end of the refrigerant return passage 14 is located slightly above the lower end of the inclined plate 18. The other end of the refrigerant return passage 14 is connected to an upper portion of the storage tank 61. (return pump)

[0090] The return pump 15 is provided in the refrigerant return channel 14. The return pump 15 pumps the refrigerant R in the housing 20 into the storage tank 61. (Return flow adjustment valve)

[0091] The return flow adjustment valve 16 is provided in the refrigerant return passage 14. The return flow adjustment valve 16 is set on the storage tank 61 side with respect to the return pump 15. That is, the return flow adjustment valve 16 is provided on the downstream side in the refrigerant return passage 14 in the flow direction of the refrigerant R with respect to the return pump 15. The return flow adjustment valve 16 opens and closes the refrigerant return passage 14. Furthermore, the return flow adjustment valve 16 adjusts the opening degree of the refrigerant return passage 14 to adjust the flow rate of the refrigerant R in the refrigerant return passage 14. (Filter)

[0092] The filter 17 is provided in the refrigerant return passage 14. The filter 17 is arranged on the storage tank 61 side with respect to the return amount adjusting valve 16. That is, the filter 17 is provided on the downstream side in the refrigerant return passage 14 with respect to the return amount adjusting valve 16 in the flow direction of the refrigerant R. The filter 17 according to the present embodiment is, for example, an activated carbon filter. (Operation and effects)

[0093] With the liquid immersion cooling device 410 according to the present embodiment, the following operation and effects are observed.

[0094] In the present embodiment, the liquid immersion cooling device 410 further includes the refrigerant return channel 14 and the filter 17. The refrigerant return channel 14 guides the refrigerant R stored in the housing 20 to the refrigerant introduction flow channel 60. The filter 17 is arranged in the refrigerant return channel 14. The filter 17 collects the impurities in the refrigerant R.

[0095] Accordingly, the liquid immersion cooling device 410 can supply the refrigerant R to the heating element 3 after passing the refrigerant R stored in the housing 20 through the filter 17. The filter 17 removes the impurities of the refrigerant R stored in the housing 20. Therefore, the refrigerant R stored in the housing 20 becomes the clean refrigerant R before being supplied to the heating element 3. Therefore, the liquid immersion cooling device 410 can use the refrigerant R stored in the housing 20 to cool the heating element 3. Therefore, the amount of refrigerant R used in the entire liquid immersion cooling device 410 is reduced.

[0096] In the present embodiment, the heat sink 11 is provided with an oil-repellent coating. That is, the heat sink 11 has an oil-repellent coating layer on its surface.

[0097] According to the present embodiment, the cooling efficiency of the cooling device is improved by the heat sink 11. Furthermore, the oil-repellent coating layer on the surface of the heat sink 11 suppresses the adhesion of the oil component to the heat sink 11. Therefore, the decrease in the cooling efficiency of the liquid immersion cooling device 410 is suppressed.

[0098] In the present embodiment, the cover 330 and the circuit board 2 are completely sealed with an epoxy resin or the like.

[0099] This suppresses the leakage of the clean refrigerant R in the cover 330 from the cover 330.

[0100] In the fourth embodiment, the filter 17 is an activated carbon filter, but the present disclosure is not limited thereto. <Fünfte Ausführungsform>

[0101] Hereinafter, a liquid immersion cooling device 510 according to a fifth embodiment of the present disclosure will be described with reference to Fig. 6. For the same configuration as the configurations of the first embodiment and the other embodiments, the same names and the same reference numerals are used, and a description thereof is omitted accordingly.

[0102] As in Fig. As shown in Fig. 6, the flow rate adjustment portion 9, which includes the circulation pump 12 and the flow rate adjustment valve 13, is provided in the refrigerant supply pipe 62. Furthermore, the heat sink 11 is provided with an oil-repellent coating, as in the fourth embodiment. Fig. 6 shows a state in which the server 1 is operating and the heating element 3 generates heat.

[0103] Furthermore, the liquid immersion cooling device 510 includes a spray area 80. (spray area)

[0104] The spray portion 80 is a mechanism for spraying a fluid onto the heating element 3. The spray portion 80 according to the present embodiment sprays the refrigerant R in the liquid phase in the housing 20 onto the heating element 3. The spray portion 80 has a spray pipe 81 and a spray pump 82. (spray pipe)

[0105] The spray tube 81 is located in the housing 20. The spray tube 81 is immersed in the refrigerant R in the housing 20. One end of the spray tube 81 is open in the housing 20. The other end of the spray tube 81 is connected to the refrigerant supply pipe 62. The spray tube 81 is connected to the refrigerant supply pipe 62. (spray pump)

[0106] The spray pump 82 is provided in the spray pipe 81. The spray pump 82 pumps the refrigerant R in the housing 20 into the cover 30. Accordingly, a high-speed flow of the refrigerant R is supplied to the heating element 3 and the heat sink 11 in the housing 20. (spray quantity adjustment valve)

[0107] A spray amount adjustment valve 83 is provided in the spray pipe 81. The spray amount adjustment valve 83 is provided on the side of the refrigerant supply pipe 62 with respect to the spray pump 82. That is, the spray amount adjustment valve 83 is arranged on the downstream side of the spray pipe 81 in the flow direction of the refrigerant R with respect to the spray pump 82. The spray amount adjustment valve 83 opens and closes the spray pipe 81. Furthermore, the spray amount adjustment valve 83 adjusts the opening degree of the spray pipe 81 to regulate the flow rate of the refrigerant R in the spray pipe 81. (Operation and effects)

[0108] The liquid immersion cooling device 510 according to the present embodiment has the following operation and effects.

[0109] In the present embodiment, the liquid immersion cooling device 510 may include a spray region 80 that sprays the liquid onto the heating element 3.

[0110] As a result, the liquid immersion cooling device 510 can spray the high-speed flow to the heating element 3 and the heat sink 11 through the spray region 80. Therefore, even in a case where the impurities, such as the oil component, are bound to the heating element 3, the liquid immersion cooling device 510 can mechanically remove the impurities bound to the heating element 3 and the heat sink 11 by the high-speed flow supplied from the spray region 80. Therefore, the decrease in the cooling efficiency of the liquid immersion cooling device 510 is suppressed. Since the high-speed flow is supplied to the heating element 3 and the heat sink 11, the cooling efficiency of the liquid immersion cooling device 510 is further improved.

[0111] In the fifth embodiment, the spray pump 82 is provided separately in addition to the circulation pump 12 and the flow rate adjustment valve 13, but the present disclosure is not limited thereto. For example, the circulation pump 12 and the flow rate adjustment valve 13 can be used as the spray portion 80. In this case, the high-speed flow of the clean refrigerant R in the storage tank 61 is sprayed onto the heating element 3 and the heat sink 11.

[0112] In the fifth embodiment, a case where the spraying portion 80 sprays the refrigerant R in the liquid phase onto the heating element 3 was described, but the present disclosure is not limited to this. The spraying portion 80 may spray the refrigerant R in the gas phase onto the heating element 3. In addition, the spraying portion 80 may also spray a fluid other than the refrigerant R onto the heating element 3.

[0113] Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the gist of the present disclosure are also included.

[0114] In each of the above-described embodiments, the opening portions 31 and 331 are open upward, but the present disclosure is not limited thereto. For example, the opening portions 31 and 331 may be provided on the side walls of the housing 20 and open in the horizontal direction.

[0115] In each of the embodiments described above, the heat sink 11 is provided separately from the covers 30 and 330, but the present disclosure is not limited thereto. The heat sink 11 may have a structure integrated with the covers 30 and 330. <Ergänzende Anmerkung>

[0116] The liquid immersion cooling devices 10, 210, 310, 410 and 510 described in the individual embodiments are understood to include, for example, the following.

[0117] (1) A first aspect relates to a liquid immersion cooling device 10, 210, 310, 410, 510 that cools a heating element 3 provided on a circuit board 2, the liquid immersion cooling device 10, 210, 310, 410, 510 comprising: a housing 20 configured to accommodate the circuit board 2 inside and store a refrigerant R in an inner lower region; a cover 30, 330 configured to surround at least the heating element 3 and have an opening region 31, 331 in at least a part of the cover 30, 330; a condensation region 40 provided above a liquid level of the refrigerant R in the housing 20 and configured to condense the refrigerant R that has evaporated;a refrigerant introduction flow channel 60 configured to guide the refrigerant R received from the refrigerant introduction portion 50 into the cover 30, 330, and a refrigerant introduction flow channel 60 configured to guide the refrigerant R received from the refrigerant introduction portion 50 into the cover 30, 330;

[0118] In the present aspect, the refrigerant R in the gas phase is condensed in the housing 20 by the condensation section 40 and then converted into the liquid phase. The refrigerant R in the liquid phase is supplied into the cover 30, 330 through the refrigerant receiving section 50 and the refrigerant introduction flow channel 60. The refrigerant R condensed from the gas phase does not contain impurities such as a non-volatile oil component. Therefore, the refrigerant R supplied into the cover 30, 330 is the clean refrigerant R with few impurities.

[0119] In addition, the refrigerant R in the cover 30, 330 is heated by the heating element 3. This creates an upward flow in the cover 30, 330. Due to the upward flow, the clean refrigerant R is sucked into the cover 30, 330 in the refrigerant introduction flow channel 60. Thus, the clean refrigerant R is always supplied to the heating element 3 while the heating element 3 generates heat.

[0120] (2) A second aspect relates to the liquid immersion cooling device 10, 210, 310, 410, 510 according to (1), in which the opening region 31, 331 can be provided above the heating element 3.

[0121] Therefore, the refrigerant R in the cover 30, 330 is likely to flow out of the cover 30, 330 through the opening portion 31, 331 due to the upward flow generated by the heating element 3.

[0122] (3) A third aspect relates to the liquid immersion cooling device 210, 410, 510 according to (1) or (2), which may further comprise: a flow rate adjustment section 9 having a circulation pump 12 configured to pump the refrigerant R in the refrigerant introduction flow channel 60 into the cover 30, wherein the flow rate adjustment section 9 is configured to adjust a flow rate via the circulation pump 12 and temporarily store the refrigerant R on an upstream side in the refrigerant introduction flow channel 60.

[0123] Consequently, the liquid immersion cooling device 210, 410, 510 can temporarily store the clean refrigerant R upstream in the refrigerant introduction flow channel 60, adjust the amount of the clean refrigerant R supplied to the heating element 3 from the circulation pump 12 via the flow rate adjustment range 9, and adjust the amount of the clean refrigerant R supplied to the heating element 3 and the timing of supplying the clean refrigerant R to the heating element 3.

[0124] (4) A fourth aspect relates to the liquid immersion cooling device 210 according to any one of aspects (1) to (3), which may further comprise: a lid portion 70 configured to open and close the opening portion 31.

[0125] Accordingly, when the heating element 3 does not generate heat, the liquid immersion cooling device 210 can close the opening portion 31 of the cover 30 and store the clean refrigerant R in the cover 30.

[0126] (5) A fifth aspect relates to the liquid immersion cooling device 210 according to (4), in which the lid portion 70 may have a check valve structure 72 for opening the opening portion 31 in the case where a pressure of the refrigerant R flowing out of the cover 30 is equal to or greater than a predetermined value.

[0127] Accordingly, the liquid immersion cooling device 210 can suppress the backflow of the refrigerant R into the cover 30 through the check valve structure 72.

[0128] (6) A sixth aspect relates to the liquid immersion cooling device 310, 410 according to any one of the aspects (1) to (5), in which the opening portion 331 can be provided at a height equal to or higher than the liquid level of the refrigerant R stored in the housing 20.

[0129] Thereby, the liquid immersion cooling device 310, 410 can suppress the inflow of the refrigerant R containing the impurities stored in the housing 20 into the cover 30 through the opening portion 331.

[0130] (7) A seventh aspect relates to the liquid immersion cooling device 410 according to any one of aspects (1) to (6), which may further include: a refrigerant return passage 14 configured to guide the refrigerant R stored in the housing 20 to the refrigerant flow passage 60; and a filter 17 provided in the refrigerant return passage 14 and configured to collect impurities in the refrigerant R.

[0131] Accordingly, the liquid immersion cooling device 410 can supply the refrigerant R to the heating element 3 after passing the refrigerant R stored in the housing 20 through the filter 17. The filter 17 removes the impurities of the refrigerant R stored in the housing 20. Therefore, the refrigerant R stored in the housing 20 becomes the clean refrigerant R before being supplied to the heating element 3. Therefore, the liquid immersion cooling device 410 can use the refrigerant R stored in the housing 20 to cool the heating element 3.

[0132] (8) An eighth aspect relates to the liquid immersion cooling device 410, 510 according to any one of aspects (1) to (7), which may further comprise: a heat sink 11 arranged in the cover 30, 330 and thermally connected to the heating element 3, wherein the heat sink 11 has an oil-repellent coating layer on a surface.

[0133] According to the present aspect, the cooling efficiency of the cooling device is improved by the heat sink 11. Furthermore, the oil-repellent coating layer on the surface of the heat sink 11 suppresses the adhesion of the oil component to the heat sink 11.

[0134] (9) A ninth aspect relates to the liquid immersion cooling device 510 according to any one of aspects (1) to (8), which may further comprise: a spraying region 80 configured to spray a fluid onto the heating element 3.

[0135] Accordingly, the liquid immersion cooling device 510 can spray a high-speed stream onto the heating element 3 through the spraying region 80. Therefore, even in a case where the impurities, such as the oil component, are bound to the heating element 3, the liquid immersion cooling device 510 can mechanically remove the impurities bound to the heating element 3 by the high-speed stream supplied from the spraying region 80. INDUSTRIAL APPLICABILITY

[0136] The present invention can be used for a liquid immersion cooling device that cools the heating element located on a circuit board. REFERENCE SYMBOL LIST 1 server 2 circuit boards 3 heating element 4 heating element bodies 5 Cooling plate 6 Power supply 7 Power supply cable 8 communication cables 9 Flow rate adjustment range 10 Liquid immersion cooling device 11 Heat sink 12 Circulation pump 13 Flow rate adjustment valve 14 Refrigerant return channel 15 Return pump 16 Return flow adjustment valve 17 filters 18 Slanted plate 20 housings 21 sub-area housings 22 upper range housings 23 Connected Wall 30 Cover 31 Opening area 40 Condensation area 41 Heat transfer tube 50 Refrigerant receiving area 51 Reception area body 52 discharge pipe 53 Lower Wall 54 side wall 55 Drain hole 60 Refrigerant introduction flow channel 61 storage tank 62 Refrigerant supply pipe 70 lid area 71 Lid area body 72 Check valve structure 73 Hinge 74 Arm 80 spray area 81 Spray tube 82 Spray pump 83 Spray quantity adjustment valve 210 Liquid immersion cooling device 310 Liquid immersion cooling device 330 Cover 331 Opening area 410 Liquid immersion cooling device 510 liquid immersion cooler R Refrigerant W Cooling water QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2022-134839

[0002]

Claims

[1] A liquid immersion cooling device that cools a heating element provided on a circuit board, the liquid immersion cooling device comprising: a housing configured to receive the circuit board therein and to store a refrigerant in an interior lower region; a cover configured to surround at least the heating element and having an opening area in at least a portion of the cover; a condensing region provided above a liquid level of the refrigerant in the housing and configured to condense the evaporated refrigerant; a refrigerant receiving area provided above the liquid level and below the condensing area and configured to receive the refrigerant in a liquid phase condensed by the condensing area; and a refrigerant introduction flow channel configured to guide the refrigerant received from the refrigerant receiving area into the cover. [2] The liquid immersion cooling device according to claim 1, wherein the opening portion is provided above the heating element. [3] The liquid immersion cooling device according to claim 1 or 2, further comprising: a flow rate adjustment portion comprising a circulation pump configured to pump the refrigerant in the refrigerant introduction flow channel into the cover, the flow rate adjustment portion being configured to adjust a flow rate by the circulation pump and temporarily store the refrigerant on an upstream side in the refrigerant introduction flow channel. [4] The liquid immersion cooling device according to claim 1 or 2, further comprising: a lid portion configured to open and close the opening portion. [5] The liquid immersion cooling device according to claim 4, wherein the lid portion has a check valve structure for opening the opening portion when a pressure of the refrigerant flowing out of the cover is equal to or greater than a predetermined value. [6] The liquid immersion cooling device according to claim 1 or 2, wherein the opening portion is provided at a height equal to or higher than the liquid level of the refrigerant stored in the case. [7] The liquid immersion cooling device according to claim 1 or 2, further comprising: a refrigerant return passage configured to guide the refrigerant stored in the housing to the refrigerant introduction flow passage; and a filter provided in the refrigerant return passage and configured to trap impurities in the refrigerant. [8] The liquid immersion cooling device according to claim 1 or 2, further comprising: a heat sink arranged in the cover and thermally connected to the heating element, wherein the heat sink has an oil-repellent coating layer on one surface. [9] The liquid immersion cooling device according to claim 1 or 2, further comprising: a spray area configured to spray a fluid onto the heating element.

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