Server system

Abstract

To provide a server system which can discharge heat efficiently and also to provide a server system which can adjust its cooling capability according to its generated heat amount.SOLUTION: A server system according to the present invention has a rack group in which a plurality of racks each for housing a heat generating body to be cooled by a coolant are arranged in parallel in a first horizontal direction, a thermal exchange part arranged to correspond to each rack to carry out thermal exchange of the coolant with air over each of the racks, and a duct forming a discharge path extending over the plurality of the thermal exchange parts in the first horizontal direction so as to discharge air subjected to thermal exchange at each of the thermal exchange parts in the first horizontal direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a server system.

Background Art

[0002] In a system provided with a heating element, it is necessary to remove the heat generated from the heating element. For example, Patent Document 1 discloses a cooling device that receives heat from a heating element to be cooled and allows a refrigerant to circulate naturally.

[0003] Also, for example, in a data center, a large number of racks for housing servers are installed in a server room. Chips such as CPUs and GPUs mounted on the servers generate heat during operation. The server may malfunction when the temperature exceeds a predetermined temperature range. Therefore, it is necessary to cool the server room. As a cooling method for the server room, for example, there is an air-cooling method in which air in the server room is cooled and circulated by an air conditioner.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when server racks are densely arranged in a limited space such as a server room, a large amount of energy is required in the air-cooling method. Therefore, constructing a system that can efficiently remove heat has been an issue. Also, when the heat generation amount of the server is large, the cooling capacity may be insufficient in the air-cooling method.

[0006] The present disclosure has been made to solve the above problems, and an object thereof is to provide a server system that can efficiently exhaust heat. The present disclosure has been made to solve the above problems, and an object thereof is to provide a server system capable of adjusting a cooling capacity according to a calorific value.

Means for Solving the Problems

[0007] In order to solve the above problems, a server system according to the present disclosure includes a rack group in which a plurality of racks for accommodating heat-generating bodies cooled by a refrigerant are arranged in parallel in a horizontal first direction, and a heat exchanger provided corresponding to each rack for exchanging heat between the refrigerant and air above each rack, and a duct formed above the plurality of heat exchangers for extending in the horizontal first direction and discharging the air heat-exchanged in each heat exchanger in the horizontal first direction.

[0008] A server system according to the present disclosure includes a rack for accommodating a heat-generating body cooled by a refrigerant, a heat exchanger provided corresponding to the rack for exchanging heat between the refrigerant and air above the rack, a duct formed above the heat exchanger for discharging the air heat-exchanged in the heat exchanger, a cooling component attached to the heat-generating body and through which the refrigerant can flow for cooling the heat-generating body by exchanging heat with the refrigerant, an air-cooling fan for blowing air to the heat exchanger to cool the heat exchanger, a refrigerant cooler for cooling the refrigerant by exchanging heat with a second refrigerant, a natural circulation flow path provided with the heat exchanger and the cooling component for naturally circulating the refrigerant by heat convection, a forced circulation flow path bypassing a part of the natural circulation flow path for forcibly circulating the refrigerant without heat convection, and a refrigerant cooling flow path bypassing a part of the natural circulation flow path and provided with the refrigerant cooler, a refrigerant circulation flow path having the above, and a switching mechanism provided in the refrigerant circulation flow path for switching the flow path of the refrigerant between a flow path through which the refrigerant passes through the forced circulation flow path and a flow path through which the refrigerant does not pass through the forced circulation flow path, and for switching the flow path of the refrigerant between a flow path through which the refrigerant passes through the refrigerant cooling flow path and a flow path through which the refrigerant does not pass through the refrigerant cooling flow path.

[0009] The server system according to the present disclosure includes a rack group in which a plurality of racks accommodating heating elements are arranged in parallel in a first horizontal direction, cooling fans provided in each of the racks to supply air to the heating elements and discharge the air that has passed through the heating elements outside the racks, and a duct that extends in the first horizontal direction above the rack group and forms a discharge flow path for discharging the air discharged from the racks by the cooling fans in the first horizontal direction.

Effect of the Invention

[0010] According to the server system of the present disclosure, heat can be efficiently exhausted. Further, according to the server system of the present disclosure, the cooling capacity can be adjusted according to the heat generation amount.

Brief Description of the Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] <First Embodiment> (Configuration of Server System) Hereinafter, the server system 1 according to the first embodiment of the present disclosure will be described with reference to FIGS. 1 to 5. As shown in FIG. 1, the server system 1 includes a server center 2, a rack group 10, a heat exchange section 20, a filter 3, a duct 30, a support member 4 (see FIG. 5), a cooling component 5 (see FIG. 4), and a refrigerant circulation flow path 40 (see FIG. 4).

[0013] (Server Center) On each floor of the server center 2, a server room 2a is provided. In each server room 2a, various devices and facilities constituting the server system 1, such as a rack group 10, a heat exchange section 20, a filter 3, a duct 30, a support member 4, a cooling component 5, and a refrigerant circulation flow path 40, are accommodated.

[0014] (Rack group) As shown in FIGS. 1 to 3, the rack group 10 is composed of a plurality of racks 11. The rack 11 is formed in a rectangular parallelepiped shape and extends in the vertical direction Dv.

[0015] Hereinafter, the depth direction Dd of the rack 11 will be simply referred to as the depth direction Dd, and the width direction Dw of the rack 11 will be simply referred to as the width direction Dw for explanation. Both the depth direction Dd and the width direction Dw are horizontal directions and are orthogonal to each other. Also, hereinafter, the depth direction Dd will be the horizontal first direction D1, and the width direction Dw will be the horizontal second direction D2. That is, the horizontal first direction D1 and the horizontal second direction D2 are orthogonal to each other.

[0016] The rack group 10 is configured by arranging a plurality of racks 11 in parallel in the horizontal first direction D1 (depth direction Dd). A plurality of rack groups 10 are provided side by side in the horizontal second direction D2 (width direction Dw).

[0017] As shown in FIG. 4, the rack 11 houses a plurality of servers 12. The plurality of servers 12 are arranged at intervals in the vertical direction Dv within the rack 11. The server 12 has a board 13 and a heating element 14 inside. The heating element 14 is a chip such as a CPU or GPU mounted on the board 13. Only one heating element 14 is shown in each board 13, but a plurality of heating elements 14 may be provided. For example, a plurality of heating elements 14 may be provided side by side in the horizontal second direction D2 (width direction Dw) on each board 13. The heating element 14 generates heat during operation. The heating element 14 is cooled by the refrigerant R circulating through the refrigerant circulation flow path 40 described later. The refrigerant R in this embodiment is, for example, water. The type of the refrigerant R can be appropriately changed. The refrigerant R may be, for example, an HFO (hydrofluoroolefin) (such as R1233zd) with a small GWP (global warming potential) and ODP (ozone depletion potential). Also, the refrigerant R may be a type of refrigerant that does not correspond to, for example, PFAS (perfluoroalkyl subsatandes an polyfluoroalkyl substances).

[0018] (Heat exchange section) As shown in FIGS. 4 and 5, the heat exchange section 20 is provided corresponding to each rack 11. In this embodiment, the heat exchange section 20 is disposed directly above the rack 11. That is, the heat exchange section 20 is provided at a position above the rack 11 and overlapping the rack 11 in the vertical direction Dv. The heat exchange section 20 is provided in a refrigerant circulation flow path 40 described later, and the refrigerant R after cooling the heating element 14 is supplied thereto. The heat exchange section 20 is a so-called radiator. The heat exchange section 20 exchanges heat between the refrigerant R and the air A above each rack 11 and dissipates the heat of the refrigerant R.

[0019] The heat exchange section 20 is formed in a linear shape that is positioned downward as it extends from one side in the horizontal second direction D2 to the other side in the horizontal second direction D2 when viewed from the horizontal first direction D1. The heat exchange section 20 includes a supply header 21 to which the refrigerant R is supplied, a discharge header 22 that discharges the refrigerant R, and a heat dissipation section 23 that connects the supply header 21 and the discharge header 22.

[0020] The supply header 21 is a tubular member extending in the horizontal first direction D1. The discharge header 22 is provided at a position spaced apart from the supply header 21 on the other side in the horizontal second direction D2 and below the supply header 21. The discharge header 22 is a tubular member extending in the horizontal first direction D1. The discharge header 22 is formed to have a smaller diameter than the supply header 21.

[0021] The heat radiating part 23 is formed in a cylindrical shape extending in the horizontal second direction D2 from the supply header 21 toward the discharge header 22. The heat radiating part 23 communicates the supply header 21 and the discharge header 22. The heat radiating part 23 is formed so as to gradually decrease in diameter toward the discharge header 22 side. The shape of the heat radiating part 23 can be changed as appropriate. The heat radiating part 23 may be formed in a cylindrical shape or a prismatic shape with a uniform thickness. The heat radiating part 23 releases the heat of the refrigerant R to the outside air. A plurality of heat radiating parts 23 are arranged in parallel in the horizontal first direction D1. Further, the heat radiating part 23 has fins 24 protruding in a flange shape from the outer peripheral surface. A plurality of fins 24 are provided side by side in the axial direction (horizontal second direction D2) of the heat radiating part 23.

[0022] (Filter) As shown in FIGS. 1 to 3, an air inlet 2b is provided in the server room 2a to introduce outside air for cooling into the server room 2a. The air inlet 2b is provided on one side in the horizontal first direction D1 with respect to the 12 groups of servers. The air inlet 2b extends in the horizontal second direction D2 and is formed over the entire area of the plurality of 12 groups of servers. The filter 3 is attached inside the air inlet 2b. The filter 3 is disposed upstream of the flow direction of the air A by the introduction fan 70 with respect to the rack group 10. The filter 3 allows the air A to flow through. The filter 3 is provided so as to be removably divided into a plurality in the horizontal second direction D2. The filter 3 collects dust and the like contained in the air A.

[0023] (Duct) The duct 30 is provided above the plurality of heat exchange parts 20 corresponding to one rack group 10. The duct 30 extends in the horizontal first direction D1 and forms a discharge flow path S for discharging the air A heat-exchanged at each heat exchange part 20 in the horizontal first direction D1. A plurality of ducts 30 are provided side by side in the horizontal second direction D2. In the present embodiment, the same number of ducts 30 as the rack groups 10 are provided.

[0024] The duct 30 includes an internal duct 31 disposed within the server center 2 (an example of a building), and an external duct 32 that communicates with the internal duct 31 and at least a part of which is disposed outside the server center 2 (an example of a building).

[0025] The internal duct 31 is supported by a support member (not shown) on the ceiling of the server room 2a. The internal duct 31 has a horizontal duct 33 that extends in the horizontal first direction D1. The horizontal duct 33 forms a horizontal discharge channel SH that extends in the horizontal first direction D1 within the discharge channel S. The horizontal duct 33 opens downward. Air A that has undergone heat exchange with the refrigerant R in the heat exchange unit 20 is introduced into the duct 30 from the downward opening of the horizontal duct 33. The horizontal duct 33 includes an upper plate 34, side plates 35, end plates 36, and partition plates 37.

[0026] The upper plate 34 extends along a horizontal plane and extends in the horizontal first direction D1. The side plates 35 are provided at both ends of the upper plate 34 in the horizontal second direction D2 and extend downward from the upper plate 34. The side plates 35 extend in the horizontal first direction D1. Adjacent ducts 30 share the side plates 35. Note that the side plates 35 do not have to be shared between adjacent ducts 30. The side plates 35 may be provided individually for each duct 30.

[0027] The end plate 36 is provided at one end of the upper plate 34 in the horizontal first direction D1. The end plate 36 extends downward from the upper plate 34. The end plate 36 connects the side plates 35 facing each other in the width direction Dw. A plurality of partition plates 37 are provided in the horizontal duct 33 at intervals in the horizontal first direction D1. The partition plates 37 are arranged at intervals downward from the upper plate 34 and partition the horizontal discharge channel SH in the horizontal first direction D1. One heat exchange unit 20 is arranged in each of the plurality of spaces partitioned by the plurality of partition plates 37. In the present embodiment, the entire heat exchange unit 20 is arranged within this horizontal duct 33.

[0028] The external duct 32 extends upward from the other end of the horizontal duct 33 in the horizontal first direction D1. The external duct 32 is formed in a cylindrical shape that extends upward along the wall surface of the server center 2. The external duct 32 forms a vertical discharge channel SV that extends in the vertical direction Dv in the discharge channel S. The external duct 32 is attached to the wall surface of the server center 2. The upper end of the external duct 32 is curved and opens downward.

[0029] (Support material) The support member 4 is provided in the duct 30 and connects the heat exchange part 20 and the duct 30. The support member 4 supports the duct 30 from below. The support member 4 is provided on the supply header 21 and the discharge header 22 respectively. Hereinafter, the support member 4 provided on the supply header 21 is referred to as the supply-side support member 4a, and the support member 4 provided on the discharge header 22 is referred to as the discharge-side support member 4b. The supply-side support member 4a extends from the supply header 21 to one side in the horizontal second direction D2 and is connected to the side plate 35. The discharge-side support member 4b extends from the discharge header 22 to the other side in the horizontal second direction D2 and is connected to the side plate 35.

[0030] (Cooling component) The cooling component 5 is attached to the heating element 14 and the refrigerant R can flow through it. The refrigerant R cools the heating element 14 by exchanging heat with the refrigerant R. The cooling component 5 is, for example, a cold plate, and the refrigerant R is supplied from a refrigerant circulation channel 40 described later. In the cooling component 5, the refrigerant R receives the heat of the heating element 14 and boils.

[0031] (Refrigerant circulation channel) The refrigerant circulation channel 40 is provided with the heat exchange part 20 and the cooling component 5 described above, and has a natural circulation channel 41 that naturally circulates the refrigerant R by heat convection. The natural circulation channel 41 includes a discharge pipe 42, a first header 43, a supply-side connection pipe 44, a discharge-side connection pipe 45, a second header 46, and a supply pipe 47. The discharge pipe 42 is provided for each cooling component 5. The discharge pipe 42 extends from the upper surface of the cooling component 5. The refrigerant R after heat exchange with the heating element 14 from the cooling component 5 is discharged into the discharge pipe 42. The plurality of discharge pipes 42 are connected to the first header 43.

[0032] The first header 43 merges the refrigerant R flowing through each discharge pipe 42. The first header 43 extends upward. The first header 43 is connected to the supply-side connection pipe 44. The first header 43 has a flange 43a that protrudes radially outward at the upper end.

[0033] The supply-side connection pipe 44 extends upward and is connected to the supply header 21 of the heat exchange section 20. The supply-side connection pipe 44 has a flange 44a that protrudes radially outward at the lower end. The flange 44a of the supply-side connection pipe 44 is fixed in a state of being overlapped with the flange 43a of the first header 43. The refrigerant R flowing through the first header 43 is supplied to the supply header 21 of the heat exchange section 20 via the supply-side connection pipe 44. Thereafter, the refrigerant R dissipates heat in the heat dissipation section 23 and is sent to the discharge header 22. A discharge-side connection pipe 45 is provided in the discharge header 22.

[0034] The discharge-side connection pipe 45 extends downward from the discharge header 22. The discharge-side connection pipe 45 has a flange 45a that protrudes radially outward at the lower end. A second header 46 is connected to the discharge-side connection pipe 45.

[0035] The second header 46 extends downward from the discharge-side connection pipe 45. The second header 46 has a flange 46a that protrudes radially outward at the upper end. The flange 45a of the discharge-side connection pipe 45 is fixed in a state of being overlapped with the flange 46a of the second header 46. The refrigerant R discharged from the discharge header 22 is sent to the second header 46 via the discharge-side connection pipe 45. The second header 46 is provided with the same number of supply pipes 47 as the cooling components 5.

[0036] The supply pipe 47 extends from the second header 46 and connects the corresponding cooling component 5 and the second header 46. The supply pipe 47 is connected below the discharge pipe 42 in the cooling component 5. The plurality of supply pipes 47 distribute and supply the refrigerant R flowing through the second header 46 to each cooling component 5.

[0037] (Cooling mechanism of the heating element) Subsequently, the cooling mechanism of the heating element 14 in the server system 1 will be described. When the server 12 operates and the heating element 14 generates heat, the refrigerant R in the cooling component 5 is heated. The heated refrigerant R becomes less dense than the refrigerant R before heating and rises. In this way, due to the heat convection generated by the heat of the heating element 14, the refrigerant R naturally circulates in the refrigerant circulation flow path 40. In the present embodiment, the refrigerant R boils and vaporizes in the cooling component 5. The vaporized refrigerant R flows into the first header 43 through the discharge pipe 42. Thereafter, the refrigerant R is supplied to the heat exchange unit 20. In the heat exchange unit 20, heat exchange is performed between the refrigerant R and the surrounding air A. As a result, the refrigerant R is cooled and liquefied.

[0038] On the other hand, the surrounding air A of the heat exchange unit 20 is heated. When the surrounding air A of the heat exchange unit 20 is heated, an upward flow is generated around the heat exchange unit 20. Due to the upward flow generated around the heat exchange unit 20, the air A that has taken heat from the refrigerant R in the heat exchange unit 20 is introduced into the upper duct 30. The air A is discharged outside the server center 2 (outside the server room 2a) through the discharge flow path S. In this way, the heat of the heating element 14 is exhausted outside the server center 2 (outside the server room 2a).

[0039] When the refrigerant R is cooled in the heat exchange unit 20, it is supplied to the cooling component 5 in a liquid state through the second header 46 and the supply pipe 47. In the cooling component 5, heat exchange is performed again between the refrigerant R supplied from the supply pipe 47 and the heating element 14. In this way, the refrigerant R circulates through the refrigerant circulation flow path 40 to cool each heating element 14, and the heat of the heating element 14 can be exhausted outside the server center 2 (outside the server room 2a) through the duct 30.

[0040] (Function and Effect) The server system 1 of this embodiment can exhibit the following function exchange. In this embodiment, the server system 1 includes a rack group 10, a heat exchange unit 20, and a duct 30. The rack group 10 is configured by arranging a plurality of racks 11 that accommodate heat-generating bodies 14 cooled by a refrigerant R in parallel in the horizontal first direction D1. The heat exchange unit 20 is provided corresponding to each rack 11 to exchange heat between the refrigerant R and the air A above each rack 11. The duct 30 is formed above several heat exchange units 20 to form an exhaust flow path S that extends in the horizontal first direction D1 and discharges the air A that has exchanged heat in each heat exchange unit 20 in the horizontal first direction D1.

[0041] The heat of the heat-generating body 14 is absorbed by the refrigerant R. The refrigerant R that has absorbed the heat of the heat-generating body 14 is sent to the heat exchange unit 20. The heat exchange unit 20 exchanges heat between the refrigerant R and the air A around the heat exchange unit 20. In this way, in the heat exchange unit 20, the heat of the heat-generating body 14 transmitted through the refrigerant R is discharged to the outside air. The duct 30 can collectively discharge the air A that has absorbed the exhaust heat from a plurality of heat exchange units 20 belonging to the corresponding rack group 10. Therefore, according to the above configuration, exhaust heat can be efficiently discharged.

[0042] <Second Embodiment> (Configuration of Server System) Hereinafter, the server system 201 according to the second embodiment of the present disclosure will be described with reference to FIGS. 6 and 7. For the same configurations as those in the above-described embodiment, the description will be appropriately omitted by assigning the same names and the same reference numerals. As shown in FIGS. 6 and 7, the server system 201 includes a support member 4 in the same manner as the server system 1 of the first embodiment.

[0043] (Support Member) Among the support members 4, a plurality of supply-side support members 4a are provided along the supply header 21, and a plurality of discharge-side support members 4b are provided along the discharge header 22. In addition, in the present embodiment, the entire heat exchange unit 20 is disposed within the duct 30.

[0044] The side plate 35 is formed with insertion holes 38 into which the support members 4 are inserted. Among the insertion holes 38, the insertion hole 38 into which the supply-side support member 4a is inserted is defined as a supply-side insertion hole 38a, and the insertion hole 38 into which the discharge-side support member 4b is inserted is defined as a discharge-side insertion hole 38b. The supply-side insertion hole 38a is provided above the discharge-side insertion hole 38b.

[0045] (Function and Effect) The server system 201 of the present embodiment can exhibit the following functions and effects. In the present embodiment, the server system 201 further includes a support member 4 that connects the heat exchange unit 20 and the duct 30. The entire heat exchange unit 20 is disposed within the duct 30. The duct 30 is formed with insertion holes 38 into which the support members 4 are inserted.

[0046] By simply inserting the support member 4 into the insertion hole 38, at least a part of the heat exchange unit 20 can be easily disposed within the duct 30. As a result, the air A exhausted from the heat exchange unit 20 is easily guided into the duct 30. Therefore, according to the above configuration, heat can be exhausted more efficiently.

[0047] In the present embodiment, it is assumed that the entire heat exchange unit 20 is disposed within the duct 30, but the present invention is not limited thereto. A part of the heat exchange unit 20 may be disposed within the duct 30.

[0048] <Third Embodiment> (Configuration of Server System) Hereinafter, a server system 301 according to a third embodiment of the present disclosure will be described with reference to FIGS. 8 and 9. For the same configurations as those in the foregoing embodiments, the description will be appropriately omitted by assigning the same names and the same reference numerals. As shown in FIGS. 8 and 9, the server system 301 further includes an elastic member 6. The elastic member 6 is disposed within the duct 30. The elastic member 6 is designed to be elastically deformable. Examples of the elastic member 6 include, for example, a rubber material or the like. Also, in the present embodiment, the entire heat exchange unit 20 is disposed within the duct 30.

[0049] (Elastic member) The elastic member 6 is provided so as to fill the gap between the heat exchange unit 20 and the duct 30. The elastic member 6 is provided on the supply header 21 and the discharge header 22, respectively. Of the elastic members 6, the elastic member 6 provided on the supply header 21 is defined as a supply-side elastic member 6a, and the elastic member 6 provided on the discharge header 22 is defined as a discharge-side elastic member 6b.

[0050] The supply-side elastic member 6a extends in the horizontal first direction D1 along the supply header 21. Both ends of the supply-side elastic member 6a are in close contact with the partition plate 37. The supply-side elastic member 6a is crushed between the outer peripheral surface of the supply header 21 and the side plate 35 of the duct 30, and is in close contact with the side plate 35 of the duct 30 and the outer peripheral surface of the supply header 21. The discharge-side elastic member 6b extends in the horizontal first direction D1 along the discharge header 22. Both ends of the discharge-side elastic member 6b are in close contact with the partition plate 37. The discharge-side elastic member 6b is crushed between the outer peripheral surface of the discharge header 22 and the side plate 35 of the duct 30, and is in close contact with the side plate 35 of the duct 30 and the outer peripheral surface of the discharge header 22.

[0051] (Function and effect) The server system 301 of the present embodiment can exhibit the following functions and effects.

[0052] In the present embodiment, the server system 301 is disposed within the duct 30 and further includes an elastically deformable elastic member 6. The entire heat exchange unit 20 is disposed within the duct 30. The elastic member 6 is provided so as to fill the gap between the heat exchange unit 20 and the duct 30.

[0053] By arranging the elastic member 6 in close contact with the heat exchange section 20 and the duct 30, it is possible to suppress the leakage of the air A exhausted from the heat exchange section 20 to the outside of the duct 30. Therefore, according to the above configuration, heat can be exhausted more efficiently.

[0054] In addition, in the present embodiment, although it is assumed that the entire heat exchange section 20 is arranged inside the duct 30, the present invention is not limited to this. A part of the heat exchange section 20 may be arranged inside the duct 30.

[0055] In addition, in the present embodiment, the case where the elastic member 6 is provided at both ends in the horizontal second direction D2 (width direction Dw) of the heat exchange section 20 has been described, but the present invention is not limited to this. The elastic member 6 may be provided so as to cover the entire circumference of the heat exchange section 20 in the horizontal direction.

[0056] <Fourth Embodiment> (Configuration of Server System) Hereinafter, the server system 401 according to the fourth embodiment of the present disclosure will be described with reference to FIG. 10. For the same configurations as those in the above-described embodiments, the description will be appropriately omitted by assigning the same names and the same reference numerals. In FIG. 10, only one duct 30 out of a plurality of ducts 30 constituting a group of ducts 30 is shown representatively. Also, only one rack group 10 out of a plurality of rack groups 10 is shown representatively, and only one rack 11 out of a plurality of racks 11 constituting one rack group 10 is shown representatively. Only one heating element 14 is shown in each board 13, but a plurality of heating elements 14 are provided at the same height in the horizontal second direction D2 (width direction Dw) on each board 13. The cooling components 5 are attached to each heating element 14 and a plurality of them are provided at the same height in the horizontal second direction D2 (width direction Dw). Note that the number of the heating elements 14 and the cooling components 5 can be changed as appropriate. For example, only one heating element 14 and one cooling component 5 may be provided on each board 13. As shown in FIG. 10, the duct 30 has a horizontal duct 33 and a second duct 39.

[0057] The second duct 39 is provided so as to be connectable to the horizontal duct 33 from below. The second duct 39 communicates with the horizontal duct 33. The second duct 39 is formed in a rectangular tube shape extending in the vertical direction Dv.

[0058] The heat exchange section 20 is surrounded by the second duct 39. Also, the heat exchange section 20 is provided integrally with the second duct 39. The heat exchange section 20 and the second duct 39 are connected by, for example, a support member 4. The support member 4 is provided so as to fill the gap between the heat exchange section 20 and the second duct 39. Also, the gap between the heat exchange section 20 and the second duct 39 may be filled by, for example, the elastic member 6 described above. Hereinafter, the integrated body of the heat exchange section 20 and the second duct 39 is referred to as a heat exchange unit U. In the present embodiment, it is assumed that the supply side connection pipe 44 and the discharge side connection pipe 45 are included in the heat exchange unit U.

[0059] The integrated body (heat exchange unit U) of the heat exchange section 20 and the second duct 39 is provided directly above the rack 11. That is, the integrated body (heat exchange unit U) of the heat exchange section 20 and the second duct 39 is provided above the rack 11 and at a position overlapping the rack 11 in the vertical direction Dv.

[0060] In the present embodiment, the first header 43 and the second header 46 are housed in the rack 11. The first header 43 extends in the vertical direction Dv. The upper end portion of the first header 43 protrudes above the rack 11. The upper end portion of the second header 46 protrudes above the rack 11. Both the first header 43 and the second header 46 are supported by the rack 11 by support members (not shown).

[0061] The heat exchange unit U is placed on the upper end portions of these first header 43 and second header 46. The flange 44a of the supply side connection pipe 44 is fixed to the flange 43a of the first header 43, and the flange 45a of the discharge side connection pipe 45 is fixed to the flange 46a of the second header 46. By doing so, the heat exchange unit U is fixed to the first header 43 and the second header 46.

[0062] Also, in the present embodiment, the server system 401 further includes a refrigerant pump 7 and a switching mechanism 60. In addition to the natural circulation flow path 41 described above, the refrigerant circulation flow path 40 has a branch portion 48 and a forced circulation flow path 49. The branch portion 48 is provided at the upstream end of the natural circulation flow path 41.

[0063] (Forced Circulation Flow Path) The forced circulation flow path 49 is provided so as to branch from the branch portion 48 and bypass a part of the natural circulation flow path 41. The upstream end of the forced circulation flow path 49 is connected to the branch portion 48, and the downstream end of the forced circulation flow path 49 is connected to the downstream end of the second header 46. A refrigerant pump 7 is provided in the forced circulation flow path 49. The refrigerant pump 7 pumps the refrigerant R. The forced circulation flow path 49 forcibly circulates the refrigerant R by the pumping force of the refrigerant pump 7 without relying on heat convection. Note that the power for the forced circulation flow path 49 to forcibly circulate the refrigerant R without relying on heat convection may be supplied from a power source other than the refrigerant pump 7.

[0064] (Switching Mechanism) The switching mechanism 60 is provided in the refrigerant circulation flow path 40. The switching mechanism 60 can switch the flow path of the refrigerant R between a flow path through which the refrigerant R passes through the forced circulation flow path 49 and a flow path through which the refrigerant R does not pass through the forced circulation flow path 49.

[0065] The switching mechanism 60 of the present embodiment includes a first valve 61 and a second valve 62. The first valve 61 is provided in the second header 46 on the downstream side of the branch portion 48 and on the upstream side of all the supply pipes 47. The second valve 62 is provided on the downstream side of the branch portion 48 in the forced circulation flow path 49.

[0066] By opening the first valve 61 and closing the second valve 62, the flow path of the refrigerant R can be set to a flow path through which the refrigerant R does not pass through the forced circulation flow path 49 (natural circulation). On one hand, by closing the first valve 61 and opening the second valve 62, the flow path of the refrigerant R can be set as a flow path through which the refrigerant R passes through the forced circulation flow path 49 (forced circulation). In this state, by driving the refrigerant pump 7, the refrigerant R can be forcibly circulated.

[0067] (Function and Effect) The server system 401 of this embodiment can exhibit the following functions and effects. In this embodiment, the duct 30 has a horizontal duct 33 and a second duct 39. The horizontal duct 33 extends in the horizontal first direction D1. The second duct 39 is provided so as to be connectable to the horizontal duct 33 from below and communicates with the horizontal duct 33. The heat exchange unit 20 is surrounded by the second duct 39 and is provided integrally with the second duct 39. The integrated body of the heat exchange unit 20 and the second duct 39 (heat exchange unit U) is provided above the rack 11 at a position overlapping the rack 11 in the vertical direction Dv.

[0068] The load of the heat exchange unit 20 can be directly received on the rack 11 side. Therefore, the stability can be improved. Furthermore, since the heat exchange unit 20, the second duct 39, and the rack 11 can be set as a set, the installation thereof becomes easy.

[0069] In this embodiment, the server system 401 includes a cooling component 5, a refrigerant pump 7, a refrigerant circulation passage 40, and a switching mechanism 60. The cooling component 5 is attached to the heating element 14, allows the refrigerant R to flow therethrough, and cools the heating element 14 by exchanging heat with the refrigerant R. The refrigerant pump 7 pumps the refrigerant R. The refrigerant circulation passage 40 has a natural circulation passage 41 and a forced circulation passage 49. The natural circulation passage 41 is provided with a heat exchange section 20 and a cooling component 5, and causes the refrigerant R to naturally circulate by heat convection. The forced circulation passage 49 bypasses a part of the natural circulation passage 41. The forced circulation passage 49 is provided with the refrigerant pump 7. The forced circulation passage 49 forcibly circulates the refrigerant R by the pumping force of the refrigerant pump 7 without relying on heat convection. The switching mechanism 60 is provided in the refrigerant circulation passage 40. The switching mechanism 60 can switch the flow path of the refrigerant R between a flow path through which the refrigerant R passes through the forced circulation passage 49 and a flow path through which the refrigerant R does not pass through the forced circulation passage 49.

[0070] When the heat generation amount is small, by switching the flow path of the refrigerant R to a flow path through which the refrigerant R does not pass through the forced circulation passage 49, the refrigerant R can be naturally circulated only by heat convection due to the heat of the heating element 14. When the heat generation amount is large, by switching the flow path of the refrigerant R to a flow path through which the refrigerant R passes through the forced circulation passage 49, the refrigerant R can be forcibly circulated without relying on heat convection. As a result, the refrigerant R can circulate smoothly, and the cooling capacity can be improved.

[0071] In this way, according to the heat generation amount, the circulation of the refrigerant R can be switched between natural circulation by heat convection only and forced circulation without heat convection by the refrigerant pump 7. Therefore, the heating element 14 can be efficiently cooled.

[0072] <Fifth Embodiment> (Configuration of Server System) Hereinafter, the server system 501 according to the fifth embodiment of the present disclosure will be described with reference to FIGS. 11 and 12. For the same configurations as those in the above-described embodiments, the same names and the same reference numerals will be given, and the description will be omitted as appropriate. In FIG. 11, only one duct 30 out of a plurality of ducts 30 constituting a group of ducts 30 is shown representatively. Also, only one rack group 10 out of a plurality of rack groups 10 is shown representatively, and only one rack 11 out of a plurality of racks 11 constituting one rack group 10 is shown representatively. Only one heating element 14 is shown in each board 13, but a plurality of heating elements 14 are provided on each board 13 at the same height in the horizontal second direction D2 (width direction Dw). The cooling components 5 are attached to each heating element 14 and a plurality of them are provided at the same height in the horizontal second direction D2 (width direction Dw). Note that the number of the heating elements 14 and the cooling components 5 can be changed as appropriate. For example, only one heating element 14 and one cooling component 5 may be provided on each board 13. Also, in this embodiment as well, the heat exchange section 20 and the second duct 39 are connected by, for example, a support member 4. The support member 4 is provided so as to fill the gap between the heat exchange section 20 and the second duct 39. Also, the gap between the heat exchange section 20 and the second duct 39 may be filled by, for example, the elastic member 6 described above. As shown in FIGS. 11 and 12, the refrigerant circulation flow path 40 includes the natural circulation flow path 41, the forced circulation flow path 49, and the refrigerant cooling flow path 50 described above.

[0073] (Refrigerant Cooling Flow Path) The refrigerant cooling flow path 50 is provided so as to further branch from the forced circulation flow path 49 and bypass a part of the natural circulation flow path 41. The upstream end of the refrigerant cooling flow path 50 is connected between the second valve 62 and the refrigerant pump 7 in the forced circulation flow path 49, and the downstream end of the refrigerant cooling flow path 50 is connected to the downstream end of the first header 43. A refrigerant cooler 9 described later is provided in the refrigerant cooling flow path 50. The server system 501 further includes an air-cooling fan 8, a refrigerant cooler 9, and a second refrigerant pump 56.

[0074] (Air-Cooling Fan) The air-cooling fan 8 blows air to the heat exchange section 20 to cool the heat exchange section 20. The air-cooling fan 8 is disposed above the heat exchange section 20 within the second duct 39. The air-cooling fan 8 is preferably provided at a position close to the heat radiation section 23 of the heat exchange section 20. The air-cooling fan 8 draws in the lower air A and blows it toward the upper horizontal duct 33.

[0075] (Refrigerant cooler) The refrigerant cooler 9 is provided in the refrigerant cooling flow path 50. The refrigerant cooler 9 is disposed below the refrigerant pump 7. In addition to the refrigerant R circulating through the refrigerant circulation flow path 40, the refrigerant cooler 9 is supplied with a second refrigerant R2 supplied from a second refrigerant flow path 55 different from the refrigerant circulation flow path 40. The refrigerant cooler 9 cools the refrigerant R by heat-exchanging it with the second refrigerant R2. The second refrigerant R2 is, for example, water. Note that the second refrigerant R2 is not limited to water and can be appropriately selected. In addition, a second refrigerant pump 56 for pumping the second refrigerant R2 is provided in the second refrigerant flow path 55.

[0076] (Switching mechanism) The switching mechanism 60 can switch the flow path of the refrigerant R between a flow path through which the refrigerant R passes through the forced circulation flow path 49 and a flow path through which the refrigerant R does not pass through the forced circulation flow path 49. Further, the switching mechanism 60 can switch the flow path of the refrigerant R between a flow path through which the refrigerant R passes through the refrigerant cooling flow path 50 and a flow path through which the refrigerant R does not pass through the refrigerant cooling flow path 50.

[0077] The switching mechanism 60 of the present embodiment includes a first valve 61, a second valve 62, a third valve 63, and a fourth valve 64. The third valve 63 is provided on the upstream side of the refrigerant cooling flow path 50. The fourth valve 64 is provided on the downstream side of the first header 43 in the natural circulation flow path 41. The fourth valve 64 is provided on the first header 43 on the downstream side of all the discharge pipes 42. In the present embodiment, by switching the first valve 61, the second valve 62, the third valve 63, and the fourth valve 64, the flow path of the refrigerant R can be selectively switched according to the heat generation amount.

[0078] An example of switching the circulation of refrigerant R will be described below with reference to FIG. 12. When the heat generation amount per heating element 14 (hereinafter referred to as the heating element heat generation amount) is 0 W or more and 500 W (the first heating element threshold value) or less, and the total heat generation amount per rack 11 (hereinafter referred to as the total heat generation amount) is 0 kW or more and 15 kW (the first rack threshold value) or less (the first condition C1), the first valve 61 and the fourth valve 64 are opened, and the second valve 62 and the third valve 63 are closed. In this case, the refrigerant R can be naturally circulated only by the heat convection generated by the heat of the heating element 14.

[0079] When the heating element heat generation amount is 500 W (the first heating element threshold value) or more and 1500 W (the second heating element threshold value) or less, and the total heat generation amount is 0 kW or more and 15 kW (the first rack threshold value) or less (the second condition C2), the second valve 62 and the fourth valve 64 are opened, and the first valve 61 and the third valve 63 are closed. In this state, the refrigerant pump 7 is driven. Thereby, the refrigerant R can be pumped by the refrigerant pump 7, and the refrigerant R can be forcibly circulated.

[0080] When the heating element heat generation amount is 0 W or more and 500 W (the first heating element threshold value) or less, and the total heat generation amount is 15 kW (the first rack threshold value) or more and 50 kW (the second rack threshold value) or less (the third condition C3), the first valve 61 and the fourth valve 64 are opened, and the second valve 62 and the third valve 63 are closed. Further, the air-cooling fan 8 is driven. Thereby, while the refrigerant R is naturally circulated only by the heat convection generated by the heat of the heating element 14, the refrigerant R can be cooled by the air-cooling fan 8.

[0081] When the calorific value of the heating element is 500 W (the first heating element threshold) or more and 1500 W (the second heating element threshold) or less, and the total calorific value is 15 kW (the first rack threshold) or more and 50 kW (the second rack threshold) or less (the fourth condition C4), the second valve 62 and the fourth valve 64 are opened, and the first valve 61 and the third valve 63 are closed. In this state, the refrigerant pump 7 is driven. Further, the air-cooling fan 8 is driven. Thereby, the refrigerant R can be pumped by the refrigerant pump 7 to forcibly circulate the refrigerant R, and the refrigerant R can be cooled by the air-cooling fan 8 while the refrigerant R is being forcibly circulated.

[0082] When the calorific value of the heating element is 0 W or more and 1500 W (the second heating element threshold) or less, and the total calorific value per rack 11 is 50 kW (the second rack threshold) or more and 100 kW (the third rack threshold) or less (the fifth condition C5), the first valve 61, the second valve 62, and the fourth valve 64 are closed, and the third valve 63 is opened. In this state, the refrigerant pump 7 and the second refrigerant pump 56 are driven. Thereby, the refrigerant R can be pumped by the refrigerant pump 7 to forcibly circulate the refrigerant R, and the refrigerant R can be cooled by the second refrigerant R2 while the refrigerant R is being forcibly circulated.

[0083] Note that specific values are shown as examples for the first to second heating element thresholds and the first to third rack thresholds, but it is not limited thereto. The first to second heating element thresholds and the first to third rack thresholds can be changed as appropriate. For example, the first rack threshold may be 12 kW and the second rack threshold may be 25 kW.

[0084] (Function and effect) The server system 501 of the present embodiment can exhibit the following function and effect. In the present embodiment, the server system 501 further includes a cooling component 5, an air-cooling fan 8, a refrigerant pump 7, a refrigerant cooler 9, a refrigerant circulation passage 40, and a switching mechanism 60. The cooling component 5 is attached to the heating element 14 and allows the refrigerant R to flow through it, cooling the heating element 14 by exchanging heat with the refrigerant R. The refrigerant pump 7 pumps the refrigerant R. The air-cooling fan 8 blows air to the heat exchange section 20 to cool the heat exchange section 20. The refrigerant cooler 9 cools the refrigerant R by exchanging heat with the second refrigerant R2. The refrigerant circulation flow path 40 includes a natural circulation flow path 41, a forced circulation flow path 49, and a refrigerant cooling flow path 50. The heat exchange section 20 and the cooling component 5 are provided in the natural circulation flow path 41, and the natural circulation flow path 41 allows the refrigerant R to circulate naturally by heat convection. The forced circulation flow path 49 bypasses a part of the natural circulation flow path 41, and the refrigerant pump 7 is provided in the forced circulation flow path 49. The forced circulation flow path 49 forcibly circulates the refrigerant R by the pumping force of the refrigerant pump 7 without relying on heat convection. The refrigerant cooling flow path 50 bypasses a part of the natural circulation flow path 41, and the refrigerant cooler 9 is provided in the refrigerant cooling flow path 50. The switching mechanism 60 can switch the flow path of the refrigerant R between a flow path in which the refrigerant R includes the forced circulation flow path 49 and a flow path in which the refrigerant R does not include the forced circulation flow path 49. Further, the switching mechanism 60 can switch the flow path of the refrigerant R between a flow path in which the refrigerant R passes through the refrigerant cooling flow path 50 and a flow path in which the refrigerant R does not pass through the refrigerant cooling flow path 50.

[0085] When the calorific value is small, by switching the flow path of the refrigerant R to a flow path through which the refrigerant R does not pass through the forced circulation flow path 49 and the refrigerant cooler 9, the refrigerant R can be circulated naturally only by heat convection caused by the heat of the heating element 14. When the calorific value is large, by switching the flow path of the refrigerant R to a flow path through which the refrigerant R passes through the forced circulation flow path 49 and driving the refrigerant pump 7, the refrigerant R can be forcibly circulated without relying on heat convection. As a result, the refrigerant R can circulate smoothly, and the cooling capacity can be improved. Also, by driving the air-cooling fan 8 to air-cool the heat exchange section 20, the cooling capacity can be improved. Further, by switching the flow path of the refrigerant R to a flow path through which the refrigerant R passes through the refrigerant cooling flow path 50 and driving the refrigerant cooler 9, the refrigerant R can be cooled, and the cooling capacity can be improved. Note that the power for the forced circulation flow path 49 to forcibly circulate the refrigerant R without relying on heat convection may be supplied from a power source other than the refrigerant pump 7. In this way, it is possible to appropriately switch between the operation by the natural circulation of the refrigerant R, the operation of forcibly circulating the refrigerant R without relying on heat convection, and the operation of improving the cooling capacity by driving the air-cooling fan 8 and the refrigerant cooler 9. Further, the operation of forcibly circulating the refrigerant R without relying on heat convection and the driving of the air-cooling fan 8 and the refrigerant cooler 9 can be appropriately combined. Therefore, according to the present embodiment, the cooling capacity can be adjusted according to the calorific value.

[0086] <Sixth Embodiment> (Configuration of Server System) Hereinafter, the server system 601 according to the sixth embodiment of the present disclosure will be described with reference to FIG. 13. For the configurations similar to those in the above-described embodiments, the description will be appropriately omitted by using the same names and the same reference numerals. As shown in FIG. 13, the server system 601 includes an introduction fan 70 and a filter 3. The introduction fan 70 generates a flow of air A in the horizontal first direction D1 and introduces the air A into the rack group 10. The introduction fan 70 is provided for each rack group 10 and is provided on one side in the horizontal first direction D1 with respect to each rack group 10. The filter 3 is arranged on the upstream side in the flow direction of the air A by the introduction fan 70 with respect to the rack group 10. The filter 3 allows the air A to flow through. The filter 3 collects dust and the like contained in the air A.

[0087] (Function and Effect) The server system 601 of the present embodiment can exhibit the following functions and effects. In the present embodiment, the server system 601 further includes an introduction fan 70 and a filter 3. The introduction fan 70 generates a flow of air A in the horizontal first direction D1 and introduces the air A into the rack group 10. The filter 3 is arranged on the upstream side in the flow direction of the air A by the introduction fan 70 with respect to the rack group 10.

[0088] Dust and the like can be removed from the air A supplied to the rack 11 by the filter 3. Further, the introduction fan 70 can compensate for the pressure loss of the air A passing through the filter 3. Therefore, the air A can be favorably introduced into the rack group 10. Therefore, according to the above configuration, exhaust heat can be more efficiently discharged.

[0089] <Seventh Embodiment> (Configuration of Server System) Hereinafter, a server system 701 according to a seventh embodiment of the present disclosure will be described with reference to FIG. 14. Regarding configurations similar to those of the above-described embodiments, the description will be appropriately omitted by assigning the same names and the same reference numerals. In FIG. 14, only one duct 30 out of a plurality of ducts 30 constituting a group of one duct 30 is illustrated representatively. Also, only a part of the plurality of rack groups 10 is illustrated representatively, and only one rack 11 out of the plurality of racks 11 constituting one rack group 10 is illustrated representatively. Only one heating element 14 is illustrated for each board 13, but a plurality of heating elements 14 are provided at the same height in the horizontal first direction D1 (depth direction Dd) for each board 13. The cooling components 5 are attached to the respective heating elements 14 and are provided in a plurality at the same height in the horizontal first direction D1 (depth direction Dd). Note that the numbers of the heating elements 14 and the cooling components 5 can be changed as appropriate. For example, only one heating element 14 and one cooling component 5 may be provided for each board 13. As shown in FIG. 14, two heat exchange units 20 are provided as a set for each corresponding rack 11. The two heat exchange units 20 constituting a set are arranged in a V shape when viewed from the horizontal first direction D1 such that the discharge header 22 is positioned below the supply header 21. In the present embodiment, the set of the two heat exchange units 20 arranged in a V shape is provided directly above the rack 11.

[0090] The supply-side connection pipe 44 extends downward from each of the two supply headers 21 and joins the first header 43. Further, the discharge-side connection pipe 45 extends downward from each of the two discharge headers 22 and joins the second header 46.

[0091] (Function and effect) The server system 701 of the present embodiment can exhibit the following functions and effects. In the present embodiment, two heat exchange units 20 are provided in a set for each corresponding rack 11. The two heat exchange units 20 constituting a set are arranged in a V shape when viewed in the horizontal first direction D1 such that the discharge header 22 is located below the supply header 21.

[0092] Thereby, the heat exchange efficiency per rack 11 can be improved. Therefore, according to the above configuration, heat can be exhausted more efficiently.

[0093] In the above embodiment, each of the two heat exchange units 20 is assumed to have a discharge header 22, but the present invention is not limited thereto. The two heat exchange units 20 may share one discharge header 22.

[0094] <Eighth Embodiment> (Configuration of Server System) Hereinafter, a server system 801 according to an eighth embodiment of the present disclosure will be described with reference to FIG. 15. For the same configurations as those in the above-described embodiments, the same names and the same reference numerals will be given, and the description will be omitted as appropriate. In FIG. 15, only one duct 30 out of a plurality of ducts 30 constituting a group of ducts 30 is shown representatively. Also, only a part of the plurality of rack groups 10 is shown representatively, and only one rack 11 out of the plurality of racks 11 constituting one rack group 10 is shown representatively. Only one heating element 14 is shown in each board 13, but a plurality of heating elements 14 are provided on each board 13 at the same height in the horizontal first direction D1 (depth direction Dd). The cooling components 5 are attached to each heating element 14 and are provided in a plurality at the same height in the horizontal first direction D1 (depth direction Dd). Note that the number of heating elements 14 and cooling components 5 can be changed as appropriate. For example, only one heating element 14 and one cooling component 5 may be provided on each board 13. As shown in Fig. 15, the two heat exchange parts 20 arranged in a V shape extend in the horizontal second direction D2 from near one end on one side of the corresponding rack 11 in the horizontal second direction D2 to near one end on one side of the adjacent rack 11 in the horizontal second direction D2 from the other side of the corresponding rack 11 in the horizontal second direction D2.

[0095] In the present embodiment, among the two heat exchange parts 20 arranged in a V shape, the heat exchange part 20 on one side in the horizontal second direction D2 is arranged directly above the rack 11, and the heat exchange part 20 on the other side in the horizontal second direction D2 is arranged directly above the passage between the racks 11.

[0096] Also, in the present embodiment as well, similar to the seventh embodiment, the supply side connection pipe 44 extends downward from each of the two supply headers 21 and merges into the first header 43. Further, the discharge side connection pipe 45 extends downward from each of the two discharge headers 22 and merges into the second header 46.

[0097] (Function and effect) The server system 801 of the present embodiment can exhibit the following functions and effects. In the present embodiment, the two heat exchange parts 20 arranged in a V shape extend in the horizontal second direction D2 from near one end on one side of the corresponding rack 11 in the horizontal second direction D2 to near one end on one side of the adjacent rack 11 in the horizontal second direction D2 from the other side of the corresponding rack 11 in the horizontal second direction D2.

[0098] Thereby, the heat exchange part 20 can be lengthened in the horizontal second direction D2, so that the heat exchange efficiency per rack 11 can be further improved. Therefore, according to the above configuration, waste heat can be discharged more efficiently.

[0099] <Ninth Embodiment> (Configuration of Server System) Hereinafter, the server system 901 according to the ninth embodiment of the present disclosure will be described with reference to FIG. 16. For the configurations similar to those of the foregoing embodiments, the same names and the same reference numerals will be used, and the description will be omitted as appropriate. In FIG. 16, only one duct 30 out of the plurality of ducts 30 constituting one group of ducts 30 is illustrated representatively. Also, only some of the plurality of rack groups 10 are illustrated representatively, and only one rack 11 out of the plurality of racks 11 constituting one rack group 10 is illustrated representatively. Only one heating element 14 is illustrated for each board 13, but a plurality of heating elements 14 are provided on each board 13 at the same height in the horizontal first direction D1 (depth direction Dd). The cooling components 5 are attached to each heating element 14, and a plurality of cooling components 5 are provided at the same height in the horizontal first direction D1 (depth direction Dd). Note that the numbers of the heating elements 14 and the cooling components 5 can be changed as appropriate. For example, only one heating element 14 and one cooling component 5 may be provided for each board 13. As shown in FIG. 16, a hot line HL or a cool line CL is provided between the adjacent rack groups 10 in the horizontal second direction D2. Then, the hot line HL and the cool line CL are provided alternately. The hot line HL and the cool line CL extend in the horizontal first direction D1 along the rack group 10. The duct 30 is provided above each hot line HL.

[0100] In the present embodiment, the heat exchange units 20 are provided in a pair of two above each hot line HL and below each duct 30. The two heat exchange units 20 constituting one pair are arranged in a V shape when viewed from the horizontal first direction D1 such that the discharge header 22 is positioned below the supply header 21.

[0101] Also, the supply side connection pipes 44 extend downward from each of the two supply headers 21. Also, the discharge side connection pipes 45 extend downward from each of the two discharge headers 22.

[0102] The supply-side connection pipe 44 belonging to the heat exchange part 20 on one side in the horizontal second direction D2 merges into the first header 43 belonging to the rack 11 on one side in the horizontal second direction D2. The supply-side connection pipe 44 belonging to the heat exchange part 20 on the other side in the horizontal second direction D2 merges into the first header 43 belonging to the rack 11 on the other side in the horizontal second direction D2. Also, the discharge-side connection pipe 45 belonging to the heat exchange part 20 on one side in the horizontal second direction D2 merges into the second header 46 belonging to the rack 11 on one side in the horizontal second direction D2. The discharge-side connection pipe 45 belonging to the heat exchange part 20 on the other side in the horizontal second direction D2 merges into the second header 46 belonging to the rack 11 on the other side in the horizontal second direction D2.

[0103] (Cooling Fan) The server system 901 further includes a cooling fan 75. The cooling fan 75 is provided in each rack 11 to supply air A to the heat-generating body 14 and discharge the air A that has passed through the heat-generating body 14 outside the rack 11. The cooling fan 75 is a fan for cooling the heat-generating body 14 such as a CPU or GPU that is pre-mounted on the server 12. The cooling fan 75 is provided, for example, so as to sandwich the heat-generating body 14 in the horizontal second direction D2. The cooling fan 75 blows air A so as to send it from the cool line CL to the hot line HL. In the hot line HL, the air A is guided to the upper duct 30 by blowing air A from both sides in the horizontal second direction D2. Then, the duct 30 discharges the air A discharged from the rack 11 in the horizontal first direction D1 through the discharge flow path S.

[0104] (Function and Effect) The server system 901 of the present embodiment can exhibit the following functions and effects. In the present embodiment, each rack 11 is further provided with a cooling fan 75 that supplies air A to the heat-generating body 14 and discharges the air A that has passed through the heat-generating body 14 outside the rack 11. The duct 30 discharges the air A discharged from the rack 11 in the horizontal first direction D1 through the discharge flow path S.

[0105] As a result, the air A can also be supplied to the heat exchange unit 20 by using the cooling fan 75 provided for directly cooling the heating element 14.

[0106] <Tenth Embodiment> (Configuration of Server System) Hereinafter, the server system 1001 according to the tenth embodiment of the present disclosure will be described with reference to FIG. 17. For the configurations similar to those in the above-described embodiments, the description will be appropriately omitted by assigning the same names and the same reference numerals. As shown in FIG. 17, a plurality (for example, two in the illustrated example) of server centers 2 (an example of a building) are provided. The external duct 32 belonging to one server center 2 is arranged to face the external duct 32 belonging to another server center 2 in the horizontal first direction D1. Note that the number of server centers 2 can be appropriately changed.

[0107] (Operational Effects) The server system 1001 of the present embodiment can exhibit the following operational effects. In the present embodiment, the external duct 32 belonging to one server center 2 is arranged to face the external duct 32 belonging to another server center 2.

[0108] As a result, a part of the external duct 32 is shielded by the server center 2. Therefore, it is possible to suppress an object heading toward the server center 2 from colliding with the external duct 32.

[0109] <Eleventh Embodiment> (Configuration of Server System) Hereinafter, the server system 1101 according to the eleventh embodiment of the present disclosure will be described with reference to FIG. 18. For the configurations similar to those in the above-described embodiments, the description will be appropriately omitted by assigning the same names and the same reference numerals. As shown in FIG. 18, a plurality of server centers 2 (an example of a building) are provided. In the illustrated example, four server centers 2 are provided in a ring shape. Note that the number of server centers 2 can be appropriately changed.

[0110] The external ducts 32 belonging to each server center 2 are provided in the gaps between adjacent server centers 2. Specifically, the external duct 32 belonging to one server center 2 (referred to as the first server center 2) is exposed outside the first server center 2 from the end on the other side in the horizontal first direction D1 of the first server center 2. Further, the external duct 32 belonging to the first server center 2 faces the end on one side in the horizontal first direction D1 of another server center 2 (referred to as the second server center 2) located on the other side in the horizontal first direction D1 with respect to the first server center 2. The plurality of server centers 2 are arranged in a ring so that the arrangement of the first server center 2 and the second server center 2 is repeated.

[0111] (Function and effect) The server system 1101 of this embodiment can exhibit the following functions and effects. In this embodiment, the external ducts 32 belonging to each server center 2 are provided in the gaps between adjacent server centers 2.

[0112] As a result, a part of the external duct 32 is shielded by the building. Therefore, it is possible to prevent an object heading towards the building from colliding with the external duct 32.

[0113] (Other embodiments) As described above, the embodiments of the present disclosure have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like within the scope not departing from the gist of the present disclosure are also included. In the above embodiment, the rack 11 is formed in a rectangular parallelepiped shape, but it is not limited to this. The shape of the rack 11 can be changed as appropriate.

[0114] In the above embodiment, the horizontal first direction D1 and the horizontal second direction D2 are orthogonal, but it is not limited to this. The angle formed by the horizontal first direction D1 and the horizontal second direction D2 may be greater than or less than 90 degrees.

[0115] In the above-described embodiment, it is assumed that the depth direction Dd of the rack 11 is the horizontal first direction D1 and the width direction Dw of the rack 11 is the horizontal second direction D2, and the duct 30 extends in the depth direction Dd of the rack 11. However, the present invention is not limited to this. Assuming that the depth direction Dd of the rack 11 is the horizontal second direction D2 and the width direction Dw of the rack 11 is the horizontal first direction D1, the duct 30 may extend in the width direction Dw of the rack 11.

[0116] In the above-described embodiment, the case where the heat exchange unit 20 includes the supply header 21, the discharge header 22, and the heat radiating unit 23 has been described. However, the present invention is not limited to this. The form of the heat exchange unit 20 can be appropriately changed.

[0117] For example, in the first embodiment and the like, in the above-described embodiment, it is assumed that the same number of ducts 30 as the rack group 10 are provided. However, the present invention is not limited to this. The number of installed ducts 30 can be appropriately changed. For example, one duct 30 extending in the horizontal second direction D2 may cover a plurality of rack groups 10 (for example, all rack groups 10).

[0118] In the above-described embodiment, it is assumed that the air A is introduced into the duct 30 from the downward opening of the horizontal duct 33. However, the present invention is not limited to this. The position of the opening for introducing the air A into the horizontal duct 33 can be appropriately changed. For example, openings may be formed in the end plate 36 or the side plate 35 of the horizontal duct 33.

[0119] In the above-described embodiment, the case where the refrigerant R boils and vaporizes in the cooling component 5 has been described. However, the present invention is not limited to this. The refrigerant R may not boil in the cooling component 5 and may circulate through the refrigerant circulation flow path 40 while remaining in a liquid state.

[0120] In the above-described embodiment, as an example of the building, the server center 2 has been cited to describe the embodiment. However, the present invention is not limited to this. The building may be a server room 2a within the server center 2.

[0121] <Appendix> The server systems 1, 201, 301, 401, 501, 601, 701, 801, 901, 1001, 1101 described in each embodiment are understood as follows, for example.

[0122] (1) In the server systems 1, 201, 301, 401, 501, 601, 701, 801, 901, 1001, 1101 according to the first aspect, a rack group 10 is configured by arranging a plurality of racks 11 side by side in the horizontal first direction D1, the racks 11 accommodating a heating element 14 cooled by a refrigerant R; a heat exchange unit 20 provided corresponding to each of the racks 11 to effect heat exchange between the refrigerant R and air A above each of the racks 11; and a duct 30 formed above the plurality of heat exchange units 20 and extending in the horizontal first direction D1 to form an exhaust flow path S for discharging the air A heat-exchanged in each of the heat exchange units 20 in the horizontal first direction D1.

[0123] The heat of the heating element 14 is absorbed by the refrigerant R. The refrigerant R that has absorbed the heat of the heating element 14 is sent to the heat exchange unit 20. The heat exchange unit 20 effects heat exchange between the refrigerant R and the air A around the heat exchange unit 20. In this way, in the heat exchange unit 20, the heat of the heating element 14 transmitted through the refrigerant R is discharged to the outside air. The duct 30 can collectively discharge the air A that has absorbed the exhaust heat from the plurality of heat exchange units 20 belonging to the corresponding rack group 10.

[0124] (2) The server system 201 according to the second aspect is the server system 201 in (1), further comprising a support member 4 connecting the heat exchange unit 20 and the duct 30, at least a part of the heat exchange unit 20 being disposed within the duct 30, and the duct 30 may be formed with insertion holes 38 into which the support member 4 is inserted.

[0125] By simply inserting the support member 4 into the insertion holes 38, at least a part of the heat exchange unit 20 can be easily disposed within the duct 30. Thereby, the air A that has been exhausted of heat from the heat exchange unit 20 is easily guided into the duct 30.

[0126] (3) The server system 301 of the third aspect is the server system 301 of (1) or (2), and is disposed in the duct 30, and further includes an elastic member 6 that can be elastically deformed. At least a part of the heat exchange unit 20 is disposed in the duct 30, and the elastic member 6 may be provided so as to fill the gap between the heat exchange unit 20 and the duct 30. Examples of the elastic member 6 include, for example, a rubber material.

[0127] By arranging the elastic member 6 in close contact with the heat exchange unit 20 and the duct 30, it is possible to suppress the leakage of the air A exhausted from the heat exchange unit 20 to the outside of the duct 30.

[0128] (4) The server system 401 of the fourth aspect is any one of the server systems 401 from (1) to (3), and the duct 30 has a horizontal duct 33 extending in the horizontal first direction D1, and a second duct 39 provided so as to be connectable to the horizontal duct 33 from below and communicating with the horizontal duct 33. The heat exchange unit 20 is surrounded by the second duct 39 and is provided integrally with the second duct 39. The integrated body of the heat exchange unit 20 and the second duct 39 may be provided above the rack 11 and at a position overlapping the rack 11 in the vertical direction Dv.

[0129] The load of the heat exchange unit 20 can be directly received on the rack 11 side.

[0130] (5) The server system 401 of the fifth aspect is any one of the server systems 401 from (1) to (4), and is attached to the heating element 14, through which the refrigerant R can flow, and cools the heating element 14 by exchanging heat with the refrigerant R. A cooling component 5, a heat exchange unit 20 and the cooling component 5 are provided, a natural circulation flow path 41 for naturally circulating the refrigerant R by thermal convection, and a part of the natural circulation flow path 41 is bypassed, and the refrigerant R is forced to circulate without depending on thermal convection. And a forced circulation flow path 49, and a refrigerant circulation flow path 40 having the same, and a switching mechanism 60 provided in the refrigerant circulation flow path 40 for switching the flow path of the refrigerant R between a flow path through which the refrigerant R passes through the forced circulation flow path 49 and a flow path through which the refrigerant R does not pass through the forced circulation flow path 49. It may be further provided.

[0131] When the calorific value is small, by switching the flow path of the refrigerant R to a flow path through which the refrigerant R does not pass through the forced circulation flow path 49, the refrigerant R can be naturally circulated only by thermal convection caused by the heat of the heating element 14. When the calorific value is large, by switching the flow path of the refrigerant R to a flow path through which the refrigerant R passes through the forced circulation flow path 49, the refrigerant R can be forced to circulate without depending on thermal convection. As a result, the refrigerant R can circulate smoothly, and the cooling capacity can be improved.

[0132] (6) The server system 501 of the sixth aspect is any one of the server systems 501 from (1) to (4), and is attached to the heating element 14, allows the refrigerant R to flow, and cools the heating element 14 by exchanging heat with the refrigerant R. A cooling component 5, an air-cooling fan 8 that blows air to the heat exchange section 20 to cool the heat exchange section 20, a refrigerant cooler 9 that cools the refrigerant R by exchanging heat with a second refrigerant R2, the heat exchange section 20 and the cooling component 5 are provided, and a natural circulation flow path 41 that allows the refrigerant R to naturally circulate by thermal convection, bypasses a part of the natural circulation flow path 41, and a forced circulation flow path 49 that forcibly circulates the refrigerant R without relying on thermal convection, bypasses a part of the natural circulation flow path 41, and a refrigerant cooling flow path 50 provided with the refrigerant cooler 9. A refrigerant circulation flow path 40 having the above, provided in the refrigerant circulation flow path 40, capable of switching the flow path of the refrigerant R between a flow path through which the refrigerant R passes through the forced circulation flow path 49 and a flow path through which the refrigerant R does not pass through the forced circulation flow path 49, and capable of switching the flow path of the refrigerant R between a flow path through which the refrigerant R passes through the refrigerant cooling flow path 50 and a flow path through which the refrigerant R does not pass through the refrigerant cooling flow path 50. It may further include a switching mechanism 60.

[0133] When the calorific value is small, by switching the flow path of the refrigerant R to a flow path through which the refrigerant R does not pass through the forced circulation flow path 49 and the refrigerant cooler 9, the refrigerant R can be naturally circulated only by thermal convection due to the heat of the heating element 14. When the calorific value is large, by switching the flow path of the refrigerant R to a flow path through which the refrigerant R passes through the forced circulation flow path 49, the refrigerant R can be forcibly circulated without relying on thermal convection. As a result, the refrigerant R can circulate smoothly, and the cooling capacity can be improved. In addition, the air-cooling fan 8 can be driven to air-cool the heat exchange section 20, and the cooling capacity can be improved. Further, by switching the flow path of the refrigerant R to a flow path through which the refrigerant R passes through the refrigerant cooling flow path 50 and driving the refrigerant cooler 9, the refrigerant R can be cooled and the cooling capacity can be improved. In this way, it is possible to appropriately switch between the operation by the natural circulation of the refrigerant R, the operation of forcibly circulating the refrigerant R without relying on heat convection, and the operation of improving the cooling capacity by driving the air-cooling fan 8 and the refrigerant cooler 9. Further, the operation of forcibly circulating the refrigerant R without relying on heat convection and the driving of the air-cooling fan 8 and the refrigerant cooler 9 can be appropriately combined.

[0134] (7) The server system 601 according to the seventh aspect is the server system 601 according to any one of (1) to (6), further including an introduction fan 70 that generates a flow of air A in the horizontal first direction D1 and introduces the air A into the rack group 10, and a filter 3 that is disposed upstream of the flow direction of the air A by the introduction fan 70 with respect to the rack group 10 and through which the air A can flow.

[0135] Dust and the like can be removed from the air A supplied to the rack 11 by the filter 3. Further, the introduction fan 70 can compensate for the pressure loss of the air A passing through the filter 3. Therefore, it is possible to satisfactorily introduce the air A into the rack group 10.

[0136] (8) The server system 701 according to the eighth aspect is the server system 701 according to any one of (1) to (7), wherein the heat exchange unit 20 is provided in a set of two for each corresponding rack 11, and the heat exchange unit 20 includes a supply header 21 to which the refrigerant R is supplied, a discharge header 22 that discharges the refrigerant R, and a heat dissipation unit 23 that connects the supply header 21 and the discharge header 22 and releases the heat of the refrigerant R to the outside air. The two heat exchange units 20 constituting the set may be arranged in a V shape when viewed from the horizontal first direction D1 such that the discharge header 22 is located below the supply header 21.

[0137] Thereby, the heat exchange efficiency per rack 11 can be improved.

[0138] (9) The server system 801 of the ninth aspect is the server system 801 of (8), wherein a plurality of the rack groups 10 are provided side by side in a second horizontal direction D2 intersecting the first horizontal direction D1, and the two heat exchange units 20 arranged in a V shape may extend in the second horizontal direction D2 from near one end of the corresponding rack 11 in the second horizontal direction D2 to near one end of the corresponding rack 11 in the second horizontal direction D2 adjacent to the other rack 11 from the other side of the second horizontal direction D2.

[0139] Thereby, the heat exchange unit 20 can be lengthened in the second horizontal direction D2, so that the heat exchange efficiency per rack 11 can be further improved.

[0140] (10) The server system 901 of the tenth aspect is the server system 901 according to any one of (1) to (9), further comprising a cooling fan 75 provided in each rack 11 for supplying air A to the heating element 14 and discharging the air A that has passed through the heating element 14 outside the rack 11, and the discharge flow path S of the duct 30 may discharge the air A discharged from the rack 11 by the cooling fan 75 in the first horizontal direction D1.

[0141] Thereby, air A can also be supplied to the heat exchange unit 20 by using the cooling fan 75 provided for directly cooling the heating element 14.

[0142] (11) The server system 501 according to the 11th aspect includes a rack 11 that houses a heating element 14 cooled by a refrigerant R, a heat exchange unit 20 provided corresponding to each rack 11 to exchange heat between the refrigerant R and air A above the rack 11, a duct 30 that forms an exhaust flow path S above the heat exchange unit 20 to discharge the air A heat-exchanged in the heat exchange unit 20, a cooling component 5 attached to the heating element 14 through which the refrigerant R can flow to exchange heat between the heating element 14 and the refrigerant R for cooling, an air-cooling fan 8 that blows air to the heat exchange unit 20 to cool the heat exchange unit 20, a refrigerant cooler 9 that cools the refrigerant R by exchanging heat with a second refrigerant R2, a natural circulation flow path 41 provided with the heat exchange unit 20 and the cooling component 5 to naturally circulate the refrigerant R by thermal convection, a forced circulation flow path 49 that bypasses a part of the natural circulation flow path 41 to forcibly circulate the refrigerant R without relying on thermal convection, a refrigerant cooling flow path 50 that bypasses a part of the natural circulation flow path 41 and is provided with the refrigerant cooler 9, a refrigerant circulation flow path 40 having these, a switching mechanism 60 provided in the refrigerant circulation flow path 40 capable of switching the flow path of the refrigerant R between a flow path through which the refrigerant R passes through the forced circulation flow path 49 and a flow path through which the refrigerant R does not pass through the forced circulation flow path 49, and capable of switching the flow path of the refrigerant R between a flow path through which the refrigerant R passes through the refrigerant cooling flow path 50 and a flow path through which the refrigerant R does not pass through the refrigerant cooling flow path.

[0143] (12) The server system 901 according to the 12th aspect includes a rack group 10 in which a plurality of racks 11 that house heating elements 14 are arranged in parallel in a horizontal first direction D1, a cooling fan 75 provided in each rack 11 to supply air A to the heating element 14 and discharge the air A that has passed through the heating element 14 outside the rack 11, and a duct 30 that extends in the horizontal first direction D1 above the rack group 10 to form an exhaust flow path S that discharges the air A discharged from the rack 11 by the cooling fan 75 in the horizontal first direction D1.

[0144] (13) The server system 1001 of the 13th aspect is any one of the server systems 1001 from (1) to (12), and further includes a building in which the duct 30 is accommodated. The duct 30 has an internal duct 31 disposed inside the building and an external duct 32 communicating with the internal duct 31 and at least a part of which is disposed outside the building. A plurality of the buildings are provided, and the external duct 32 belonging to one of the buildings may be disposed opposite to the external duct 32 belonging to another one of the buildings. Examples of the building include, for example, the server center 2, the server room 2a, and the like.

[0145] Thereby, a part of the external duct 32 is shielded by the building. Therefore, it is possible to suppress an object heading for the building from colliding with the external duct 32.

[0146] (14) The server system 1101 of the 14th aspect is any one of the server systems 1101 from (1) to (12), and further includes a building in which the duct 30 is accommodated. The duct 30 has an internal duct 31 disposed inside the building and an external duct 32 communicating with the internal duct 31 and at least a part of which is disposed outside the building. A plurality of the buildings are provided, and the external duct 32 belonging to each of the buildings may be provided in a gap between adjacent ones of the buildings. Examples of the building include, for example, the server center 2, the server room 2a, and the like.

[0147] Thereby, a part of the external duct 32 is shielded by the building. Therefore, it is possible to suppress an object heading for the building from colliding with the external duct 32.

Explanation of Reference Numerals

[0148] 1... Server system 2... Server center (building) 2a... Server room 2b... Air inlet 3... Filter 4... Support member 4a... Supply-side support member 4b... Discharge-side support member 5... Cooling component 6... Elastic member 6a... Supply-side elastic member 6b... Discharge-side elastic member 7... Refrigerant pump 8... Air-cooling fan 9... Refrigerant cooler 10... Rack group 11... Rack 12... Server 13... Board 14... Heat-generating body 20... Heat exchange section 21... Supply header 22... Discharge header 23... Heat dissipation section 24... Fin 30... Duct 31... Internal duct 32... External duct 33... Horizontal duct 34... Upper plate 35... Side plate 36... End plate 36... Partition plate 38... Insertion hole 38a... Supply-side insertion hole 38b... Discharge-side insertion hole 39... Second duct 40... Refrigerant circulation flow path 41... Natural circulation flow path 42... Discharge pipe 43... First header 43a... Flange 44... Supply-side connection pipe 44a... Flange 45... Discharge-side connection pipe 45a... Flange 46... Second header 46a... Flange 47... Supply pipe 48... Branch section 49... Forced circulation flow path 50... Refrigerant cooling flow path 55... Second refrigerant flow path 56... Second refrigerant pump 60... Switching mechanism 61... First valve 62... Second valve 63... Third valve 64... Fourth valve 70... Introduction fan 75... Cooling fan 201... Server system 301... Server system 401... Server system 501... Server system 601... Server system 701... Server system 801... Server system 901... Server system 1001... Server system 1101... Server system A... Air Dv... Vertical direction Dd... Depth direction Dw... Width direction D1... Horizontal first direction D2... Horizontal second direction HL... Hot line CL... Cool line R... Refrigerant R2... Second refrigerant S... Discharge flow path SH... Horizontal discharge flow path SV... Vertical discharge flow path U... Heat exchange unit

Claims

1. A rack group configured by arranging a plurality of racks for accommodating heat generating bodies cooled by a refrigerant in parallel in a horizontal first direction, A heat exchange unit provided corresponding to each of the racks, for exchanging heat between the refrigerant and air above each of the racks, Above a plurality of the heat exchange units, a duct that extends in the horizontal first direction and forms an exhaust flow path for discharging the air heat-exchanged by each of the heat exchange units in the horizontal first direction, A server system comprising the above.

2. Further comprising a support member connecting the heat exchange unit and the duct, At least a part of the heat exchange unit is disposed within the duct, An insertion hole into which the support member is inserted is formed in the duct, The server system according to Claim 1.

3. Further comprising an elastic member disposed within the duct and capable of elastic deformation, At least a part of the heat exchange unit is disposed within the duct, The elastic member is provided so as to fill a gap between the heat exchange unit and the duct, The server system according to Claim 1 or 2.

4. The duct A horizontal duct extending in the horizontal first direction, A second duct provided so as to be connectable to the horizontal duct from below and communicating with the horizontal duct, The heat exchange unit is surrounded by the second duct and provided integrally with the second duct, The integral body of the heat exchange unit and the second duct is provided above the rack and at a position vertically overlapping the rack, The server system according to Claim 1 or 2.

5. A cooling component that is attached to the heating element, allows the refrigerant to flow therethrough, and cools the heating element by exchanging heat with the refrigerant. A natural circulation flow path in which the heat exchange part and the cooling component are provided and the refrigerant is naturally circulated by heat convection, and a forced circulation flow path that bypasses a part of the natural circulation flow path and forcibly circulates the refrigerant without relying on heat convection. A refrigerant circulation flow path having: A switching mechanism provided in the refrigerant circulation flow path and capable of switching the flow path of the refrigerant between a flow path through which the refrigerant passes through the forced circulation flow path and a flow path through which the refrigerant does not pass through the forced circulation flow path. The server system according to claim 1 or 2, further comprising:

6. A cooling component that is attached to the heating element, allows the refrigerant to flow therethrough, and cools the heating element by exchanging heat with the refrigerant. An air-cooling fan that blows air to the heat exchange part to cool the heat exchange part. A refrigerant cooler that cools the refrigerant by exchanging heat with a second refrigerant. A natural circulation flow path in which the heat exchange part and the cooling component are provided and the refrigerant is naturally circulated by heat convection, a forced circulation flow path that bypasses a part of the natural circulation flow path and forcibly circulates the refrigerant without relying on heat convection, and a part of the natural circulation flow path. A refrigerant circulation flow path having a bypassed refrigerant cooling flow path provided with the refrigerant cooler. A switching mechanism provided in the refrigerant circulation flow path, capable of switching the flow path of the refrigerant between a flow path through which the refrigerant passes through the forced circulation flow path and a flow path through which the refrigerant does not pass through the forced circulation flow path, and capable of switching the flow path of the refrigerant between a flow path through which the refrigerant passes through the refrigerant cooling flow path and a flow path through which the refrigerant does not pass through the refrigerant cooling flow path. The server system according to claim 1 or 2, further comprising:

7. An introduction fan that generates a flow of air in the horizontal first direction and introduces air into the rack group. A filter that is disposed upstream of the flow direction of the air by the introduction fan with respect to the rack group and through which air can flow. The server system according to claim 1 or 2, further comprising

8. The heat exchange part is provided in a set of two for each corresponding rack, The heat exchange part A supply header to which the refrigerant is supplied, A discharge header for discharging the refrigerant, A heat dissipation part that connects the supply header and the discharge header and releases the heat of the refrigerant to the outside air, and has The two heat exchange parts constituting the set are arranged in a V shape when viewed from the horizontal first direction such that the discharge header is located below the supply header. The server system according to claim 1 or 2.

9. A plurality of the rack groups are provided side by side in a horizontal second direction intersecting the horizontal first direction, The two heat exchange parts arranged in a V shape extend in the horizontal second direction from near one end of the corresponding rack in the horizontal second direction to near one end of the adjacent rack in the horizontal second direction from the other side of the corresponding rack in the horizontal second direction. The server system according to claim 8.

10. Each rack is further provided with a cooling fan that supplies air to the heat generating body and discharges the air that has passed through the heat generating body outside the rack, The discharge flow path of the duct discharges the air discharged from the rack by the cooling fan in the horizontal first direction. The server system according to claim 1 or 2.

11. A rack that houses a heat generating body cooled by a refrigerant, A heat exchange part provided corresponding to the rack for exchanging heat between the refrigerant and air above the rack, A duct that forms a discharge flow path for discharging the air heat-exchanged by the heat exchange part above the heat exchange part, A cooling component that is attached to the heating element, allows the refrigerant to flow through, and cools the heating element by exchanging heat with the refrigerant. An air-cooling fan that blows air to the heat exchange section to cool the heat exchange section. A refrigerant cooler that cools the refrigerant by exchanging heat with a second refrigerant. A natural circulation flow path in which the heat exchange section and the cooling component are provided and the refrigerant is naturally circulated by heat convection, a forced circulation flow path that bypasses a part of the natural circulation flow path and forcibly circulates the refrigerant without relying on heat convection, and a refrigerant cooling flow path that bypasses a part of the natural circulation flow path and in which the refrigerant cooler is provided. A switching mechanism provided in the refrigerant circulation flow path, capable of switching the flow path of the refrigerant between a flow path through which the refrigerant passes through the forced circulation flow path and a flow path through which the refrigerant does not pass through the forced circulation flow path, and also capable of switching the flow path of the refrigerant between a flow path through which the refrigerant passes through the refrigerant cooling flow path and a flow path through which the refrigerant does not pass through the refrigerant cooling flow path. A server system comprising the above.

12. A rack group in which a plurality of racks for housing heating elements are arranged in parallel in a horizontal first direction. A cooling fan provided in each of the racks, supplying air to the heating element and discharging the air that has passed through the heating element outside the rack. Above the rack group, a duct that extends in the horizontal first direction and forms a discharge flow path for discharging the air discharged from the rack by the cooling fan in the horizontal first direction. A server system comprising the above.

13. Further comprising a building in which the duct is housed. The duct is An internal duct disposed inside the building. An external duct that communicates with the internal duct and at least a part of which is disposed outside the building. And has A plurality of the buildings are provided. The external duct belonging to one of the buildings is arranged to face the external duct belonging to the other building. The server system according to any one of claims 1, 11, and 12.

14. Further comprising a building in which the duct is accommodated, The duct is an internal duct arranged in the building, an external duct communicating with the internal duct and at least a part of which is arranged outside the building, and has A plurality of the buildings are provided, The external duct belonging to each of the buildings is provided in a gap between adjacent buildings. The server system according to any one of claims 1, 11, and 12.

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