COOLING SYSTEM

Abstract

A cooling system comprises a cooling unit configured to have a plurality of cooling devices that cool a heat-generating body, an inlet manifold that distributes a refrigerant to the cooling devices, and an outlet manifold from which the refrigerant is discharged by each of the cooling devices, a natural circulation section configured to have a natural circulation line connecting the outlet manifold and the inlet manifold, and a first heat exchanger installed at a midpoint of the natural circulation line and above the cooling unit, and a forced circulation section configured to have a forced circulation line connecting the outlet manifold and the inlet manifold, a second heat exchanger,which is provided in the middle of the forced circulation line and has a larger capacity than the first heat exchanger, and a pump provided in the forced circulation line to pump the refrigerant from the outlet-side distributor to the inlet-side distributor.

Description

TECHNICAL AREA

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

[0002] The priority of Japanese patent application No. 2023-086837, filed on May 26, 2023, is claimed and the contents of which are hereby incorporated by reference. TECHNICAL BACKGROUND

[0003] Electronic devices, such as computers and servers located in a server room or similar environment, generate heat during operation. To cool such heat-generating devices, a cooling system, as shown in Patent Document 1, has been developed. The cooling system in Patent Document 1 has two circulation mechanisms: a natural circulation mechanism and a forced circulation mechanism for a refrigerant between an evaporator and a condenser. These two circulation mechanisms can be switched between. The natural circulation mechanism utilizes the heat generated by the heat-generating device to circulate the refrigerant naturally. In the forced circulation mechanism, however, the refrigerant is forced into circulation by means of a pump. Citation list patent document

[0004] Patent document 1: Unexamined Japanese patent application, first publication no. 2010-190553 SUMMARY OF THE INVENTION Technical Problem

[0005] In the cooling system described in patent document 1, however, the cooling of the refrigerant after heat exchange with the heat-generating body is carried out using a common condenser for both the natural circulation mechanism and the forced circulation mechanism. Therefore, if the cooling capacity of the condenser is insufficient for a given amount of heat, the cooling efficiency of the heat-generating body can also be reduced when switching from the natural circulation mechanism to the forced circulation mechanism.

[0006] The present disclosure was made to solve the problems mentioned above, and one objective of the present disclosure is to provide a cooling system that can improve cooling efficiency. Solution to the problem

[0007] To achieve the aforementioned objectives, a cooling system according to the present disclosure comprises a cooling unit configured to have a plurality of cooling devices that cool a heat-generating body, an inlet-side distributor that distributes a refrigerant to the cooling devices, and an outlet-side distributor from which the refrigerant is discharged by each of the cooling devices, a natural circulation section configured to have a natural circulation line connecting the outlet-side distributor and the inlet-side distributor, and a first heat exchanger installed at a midpoint of the natural circulation line and above the cooling unit, and a forced circulation section configured to have a forced circulation line connecting the outlet-side distributor and the inlet-side distributor, a second heat exchanger,which is provided in the middle of the forced circulation line and has a larger capacity than the first heat exchanger, and a pump provided in the forced circulation line to pump the refrigerant from the outlet-side distributor to the inlet-side distributor.

[0008] A cooling system according to the present disclosure comprises a cooling unit configured to have a plurality of cooling devices that cool a heat-generating body, an inlet-side distributor that distributes a refrigerant to the cooling devices, and an outlet-side distributor from which the refrigerant is discharged from each of the cooling devices, a natural circulation section configured to have a natural circulation line connecting the outlet-side distributor and the inlet-side distributor, and a first heat exchanger installed at a midpoint of the natural circulation line and above the cooling unit, and a forced circulation section configured to have a forced circulation line connecting a downstream side of the first heat exchanger in the natural circulation line and the inlet-side distributor, and a pump.which is provided in the forced circulation line to pump the refrigerant from the outlet-side distributor to the inlet-side distributor, wherein the natural circulation line has an inlet line arranged above the plurality of cooling devices to introduce the refrigerant subjected to heat exchange in the first heat exchanger into the inlet-side distributor, and the pump is arranged below the plurality of cooling devices.

[0009] A cooling system according to the present disclosure comprises a cooling unit configured to have a plurality of cooling devices that cool a heat-generating body, an inlet-side distributor that distributes a refrigerant to the cooling devices, and an outlet-side distributor from which the refrigerant is discharged from each of the cooling devices, a natural circulation section configured to have a natural circulation line connecting the outlet-side distributor and the inlet-side distributor, a first heat exchanger installed at a center of the natural circulation line and above the cooling unit, and a passage configured to be located above the first heat exchanger and extending in an upward-downward direction, the passage having an internal exhaust air flow path that carries air away from bottom to top.Advantageous effects of the invention.

[0010] The cooling system described in this disclosure makes it possible to improve cooling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS [ Fig. 1] A schematic view of a cooling system according to a first embodiment of the present disclosure. [ Fig. 2] A system diagram showing the overall configuration of the cooling system according to the first embodiment of the present disclosure. [ Fig. 3] A perspective view of a first heat exchanger according to the first embodiment of the present disclosure. [ Fig. 4] A functional block diagram of a control unit according to the first embodiment of the present disclosure. [ Fig. 5: A diagram showing a state in which a flow system for a refrigerant according to the first embodiment of the present disclosure has switched to a natural circulation line. [ Fig. 6] A flow diagram showing a method for switching the flow system for the refrigerant according to the first embodiment of the present disclosure. [ Fig. 7] A diagram showing a state in which the refrigerant flow system according to the first embodiment of the present disclosure is switched to a forced circulation line. [ Fig. 8] A system diagram showing the overall configuration of a cooling system according to a first modification example of the first embodiment of the present disclosure. [ Fig. 9] A perspective view of a first heat exchanger according to a second modification example of the first embodiment of the present disclosure. [ Fig. 10] View of the first heat exchanger according to the second modification example of the first embodiment of the present disclosure, seen from above. [ Fig. 11 ] A system diagram showing the overall configuration of a cooling system according to a second embodiment of the present disclosure. [ Fig. 12] A functional block diagram of a control unit according to the second embodiment of the present disclosure. [ Fig. 13] A flow diagram showing a method for switching a flow system for a refrigerant according to the second embodiment of the present disclosure. [ Fig. 14] A system diagram showing the overall configuration of a cooling system according to a first modification example of the second embodiment of the present disclosure. [ Fig. A system diagram showing the overall configuration of a cooling system according to a second modification example of the second embodiment of the present disclosure. [ Fig. 16] A system diagram showing the overall configuration of a cooling system according to a third embodiment of the present disclosure. [ Fig. 17] A perspective view of a first heat exchanger according to the third embodiment of the present disclosure. [ Fig. 18] A hardware configuration diagram according to the embodiments of the present disclosure. DESCRIPTION OF THE EXECUTION FORMS<Erste Ausführungsform> (Configuration of the cooling system)

[0011] A cooling system 1 according to an embodiment of the present disclosure is described below with reference to the Fig. 1 to 7 described.

[0012] As in the Fig. 1 and Fig. As shown in Figure 2, the cooling system 1 comprises a server rack 2, a server 3, a cooling unit 10, a natural circulation section 20, a forced circulation section 30, a switching section 40, a storage section 50, a passage 60, a sensor 4 and a control unit 70.

[0013] Fig. 1 and Fig. Figure 2 schematically shows each configuration of the cooling system 1. Furthermore, the Fig. 1 and Fig. 2. A part of the configuration, such as a pipe through which a refrigerant R as described below flows, or the server rack 2, has been omitted.

[0014] In the following, a vertical up-down direction can simply be referred to as "up-down direction Dv". Furthermore, the symbol "Dvu" is assigned to a top side and the symbol "Dvd" to a bottom side. (Server rack)

[0015] Server Rack 2 is an enclosure that extends in the vertical direction Dv. Server Rack 2 is installed, for example, in a data center. Server Rack 2 can house a large number of servers 3. Additionally, other devices can be placed on an upper shelf 2a of Server Rack 2. (Server)

[0016] The majority of Server 3 are arranged in Server Rack 2 in the upward-downward direction Dv.

[0017] The server 3 has a case 3a, a server board 3b and a heat generating unit 3c.

[0018] The enclosure 3a is a box-shaped enclosure that extends horizontally. Enclosure 3a is inserted transversely in the server rack 2. The server board 3b and the heat sink 3c are housed inside enclosure 3a. The server board 3b extends horizontally. (Heat-generating body)

[0019] The heat-generating element 3c is an electronic component located on the server board 3b. The heat-generating element 3c is, for example, a chip such as a CPU or a GPU, installed on the server board 3b. A number of heat-generating elements 3c are arranged horizontally on the server board 3b. Fig. Figure 2 shows, for simplicity, a case in which one heat-generating element 3c is installed for each server board 3b. The number of heat-generating elements 3c installed in a server board 3b can be changed as needed. The heat-generating elements 3c generate heat during operation. Each heat-generating element 3c has a temperature range in which it can operate most efficiently. The cooling system 1 cools each heat-generating element 3c to this temperature range. (Cooling unit)

[0020] The cooling unit 10 has a cooling device 11, an inlet-side distributor 12, an inlet-side branch line 13, a valve 14, an outlet-side distributor 15 and an outlet-side branch line 16. (Cooling device)

[0021] A plurality of cooling devices 11 are provided. The number of cooling devices 11 can be changed as needed. The cooling device 11 is attached to each of the multiple heat-generating bodies 3c. The multiple cooling devices 11 cool the connected heat-generating bodies 3c. The refrigerant R is supplied to the cooling device 11. Examples of refrigerant R are hydrofluorocarbons (HFC) and fluoroolefin refrigerants (HFO). A flow path is formed within the cooling device 11 through which the refrigerant R flows. The cooling device 11 facilitates heat exchange between the refrigerant R flowing within it and the heat-generating body 3c in order to cool the heat-generating body 3c. The cooling device 11 of the present embodiment is a box-shaped cold plate 11a in which the refrigerant R can flow. (Inlet-side distributor)

[0022] The inlet-side distributor 12 distributes the refrigerant R to each cooling unit 11. The inlet-side distributor 12 extends in the up-down direction Dv. Several inlet-side branch lines 13 are provided in the inlet-side distributor 12 for each cooling unit 11. Each inlet-side branch line 13 connects the inlet-side distributor 12 to the cooling unit 11. The branch line directs the refrigerant R distributed by the inlet-side distributor 12 to the cooling unit 11. Furthermore, a valve 14 is provided in each inlet-side branch line 13. The valve 14 is, for example, a needle valve and can open and close the inlet-side branch line 13. (Outlet-side distributor)

[0023] The refrigerant R is discharged from each cooling unit 11 into the outlet distributor 15. The outlet distributor 15 extends in the up-down direction Dv. Several outlet branch lines 16 are provided in the outlet distributor 15 for each cooling unit 11. Each outlet branch line 16 connects the outlet distributor 15 to each cooling unit 11. The refrigerant R, heated by heat exchange with the heat-generating element 3c in each cooling unit 11, flows into the outlet distributor 15 via the outlet branch line 16. (Section with natural circulation)

[0024] The natural circulation section 20 utilizes an upward flow generated by the heating of the refrigerant R due to the waste heat from the heat-generating body 3c to effect natural circulation of the refrigerant R. The natural circulation section 20 comprises a natural circulation line 21, a first heat exchanger 22, a fan 23, and a relief valve 24. The natural circulation line 21 connects the outlet manifold 15 and the inlet manifold 12. The first heat exchanger 22 is installed midway along the natural circulation line 21 and above the cooling unit 10. Each configuration of the natural circulation section 20 is described in detail below. (Natural circulation)

[0025] The natural circulation line 21 has a first natural circulation line 21a, a second natural circulation line 21b, and an inlet line 21c. The first natural circulation line 21a connects an upper end section of the outlet distributor 15 and the first heat exchanger 22. The first natural circulation line 21a carries the refrigerant R from the outlet distributor 15 to the first heat exchanger 22. The heat exchange of the refrigerant R takes place in the first heat exchanger 22. The second natural circulation line 21b extends downwards from the first heat exchanger 22 and is connected to a tank 34 of the forced circulation section 30 described below. (Entrance management)

[0026] The inlet line 21c is a bypass line that bypasses the second natural circulation line 21b. The inlet line 21c is located above the plurality of cooling devices 11. The refrigerant R, which undergoes heat exchange in the first heat exchanger 22, is fed into the inlet line 21c via the second natural circulation line 21b. The inlet line 21c introduces the refrigerant R, which undergoes heat exchange in the first heat exchanger 22, into the inlet-side distributor 12. (First heat exchanger)

[0027] The first heat exchanger 22 cools the refrigerant R, which undergoes heat exchange with the heat-generating body 3c in the cooling unit 11. A flow path is formed within the first heat exchanger 22 through which the refrigerant R can flow. The fan 23 is installed near the first heat exchanger 22. The fan 23 blows air towards the first heat exchanger 22 to supply it with air A. The first heat exchanger 22 is an air-cooling radiator 25 that facilitates heat exchange between the air A surrounding the first heat exchanger 22 and the refrigerant R, thereby cooling the refrigerant R.

[0028] As in Fig. As shown in Figure 3, two first heat exchangers 22 are arranged on the upper plate 2a of the server rack 2. Each first heat exchanger 22 is designed in the form of a flat plate. The first heat exchanger 22 has an inlet section 25a, to which the refrigerant R is supplied from the outlet distributor 15, and an outlet section 25b, which discharges the refrigerant R towards the inlet distributor 12. The first heat exchanger 22 is installed such that it is inclined with respect to a horizontal plane HL, so that the inlet section 25a is located above the outlet section 25b. More precisely, the two first heat exchangers 22 are arranged so that they are inclined in a V-shape when viewed from the horizontal direction.

[0029] Furthermore, the first heat exchanger 22 is equipped with a relief valve 24, which allows gas inside the first heat exchanger 22 to escape, so that a pressure equal to or greater than a design pressure is not present. (Forced circulation section)

[0030] The forced circulation section 30 is separate from the natural circulation section 20 and is a mechanism that circulates the refrigerant R independently of the heating of the refrigerant R due to the waste heat from the heat-generating body 3c. The forced circulation section 30 comprises a forced circulation line 31, a separate coolant distribution unit (CDU) 32, a cooling device 33, the tank 34, and a pump 35. The forced circulation line 31 connects the outlet distributor 15 and the inlet distributor 12. The separate CDU 32 has a second heat exchanger 36, which is located in the center of the forced circulation line 31. The tank 34 and the pump 35 are located on the downstream side of the second heat exchanger 36 in the forced circulation line 31. Each configuration of the forced circulation section 30 is described in detail below. (Forced circulation line)

[0031] The forced circulation line 31 has a first forced circulation line 31a, a second forced circulation line 31b, and a third forced circulation line 31c. The first forced circulation line 31a connects a lower end section of the outlet-side distributor 15 and the second heat exchanger 36. The first forced circulation line 31a carries the refrigerant R from the outlet-side distributor 15 to the second heat exchanger 36, which is described below. The heat exchange of the refrigerant R takes place in the second heat exchanger 36. The second forced circulation line 31b connects the second heat exchanger 36 to the tank 34, which is described below. The second forced circulation line 31b carries the refrigerant R, which undergoes heat exchange in the second heat exchanger 36, to the tank 34. The refrigerant R is temporarily stored in the tank 34.The third forced circulation line 31c connects the tank 34 to a lower end section of the inlet-side distributor 12. The third forced circulation line 31c directs the refrigerant R, which is supplied to the tank 34, to the inlet-side distributor 12.

[0032] The third forced circulation line 31c has a plurality of pump lines 37 in which the pump 35 is arranged, as well as a merging line 38 into which the plurality of pump lines 37 open. In the present embodiment, two pump lines 37 are provided. However, only one pump line 37 or a plurality of three or more pump lines 37 may also be provided. Each pump line 37 extends from the tank 34 and is connected to a merging line 38. The merging line 38 connects the plurality of pump lines 37 and the lower end section of the inlet-side distributor 12. (Separate CDU)

[0033] The separate CDU 32 is provided separately from the first heat exchanger 22 and is a mechanism that cools the refrigerant R, which is heated by heat exchange with the heat-generating body 3c. The second heat exchanger 36 is located in the separate CDU 32. (Second heat exchanger)

[0034] The second heat exchanger 36 is arranged on the underside Dvd with respect to the cooling unit 10. In particular, in the present embodiment, the second heat exchanger 36 is arranged below the cooling unit 10. The underside Dvd with respect to the cooling unit 10 is not limited to the case in which the second heat exchanger 36 is arranged below the cooling unit 10, and also includes a case in which the second heat exchanger 36 is arranged at the same level as a lower section of the cooling unit 10 in the upward-downward direction Dv.

[0035] The refrigerant R is supplied to the second heat exchanger 36 from the heat-generating body 3c via the first forced circulation line 31a. The second heat exchanger 36 causes the refrigerant R to undergo heat exchange in order to cool the refrigerant R. The second heat exchanger 36 has a larger capacity than the first heat exchanger 22. The second heat exchanger 36 of the present embodiment is a water-cooling plate type heat exchanger that carries out heat exchange between the refrigerant R and a cooling water W flowing inside the second heat exchanger 36 in order to cool the refrigerant R.

[0036] The second heat exchanger 36 has a plurality of water cooling plates 36a and valves 36b, which are provided on an upstream and a downstream side of each water cooling plate 36a to be able to block the flow of the refrigerant R. The plurality of water cooling plates 36a are connected in parallel. The multiple water cooling plates 36a can be connected in series. The multiple water cooling plates 36a are supplied with the refrigerant R via the first forced circulation line 31a and with the cooling water W from the outside. The heat exchange between the refrigerant R and the cooling water W takes place in each water cooling plate 36a. Accordingly, the refrigerant R is cooled and the cooling water W is heated by the waste heat of the refrigerant R. The heated cooling water W is supplied to the cooling device 33. (Cooling device)

[0037] The cooling unit 33 cools the refrigerant R, which undergoes heat exchange in the second heat exchanger 36. The refrigerant R cooled by the cooling unit 33 is then returned to the second heat exchanger 36, and heat exchange is carried out with the refrigerant R. (Pump)

[0038] The pump 35 pumps the refrigerant R from the outlet distributor 15 towards the inlet distributor 12. The refrigerant R pumped by the pump 35 is distributed from the inlet distributor to each cooling unit 11 to circulate in the cooling system 1. One pump 35 is arranged in each pump line 37. In the present embodiment, two pumps 35 are installed for each cooling unit 10. Furthermore, the two pumps 35 are arranged below the majority of the cooling units 11. As shown in the drawing, the pump 35 is located, for example, in one of the lowest compartments in the server rack 2. The pump 35 in the present embodiment is a gear pump in which an internal gear rotates to draw in and pump the refrigerant R. (Switching section)

[0039] The switching section 40 is a mechanism that switches a refrigerant flow system 6 to at least one of the natural circulation line 21 and the forced circulation line 31. The refrigerant flow system 6 is a flow path through which the refrigerant R flows. The flow system 6 comprises the natural circulation line 21 and the forced circulation line 31. This means that the switching section 40 can switch the refrigerant R so that it can flow either in the natural circulation line 21 or in the forced circulation line 31, or in both the natural circulation line 21 and the forced circulation line 31.

[0040] The switching section 40 has a first switching valve 41, a second switching valve 42, a third switching valve 43, a fourth switching valve 44, a fifth switching valve 45 and a sixth switching valve 46.

[0041] The first switching valve 41 is located in the first natural circulation line 21a. The first switching valve 41 opens and closes the first natural circulation line 21a.

[0042] The second switching valve 42 is located at a lower end section of the second natural circulation line 21b. The second switching valve 42 is located near the tank 34. The second switching valve 42 opens and closes the second natural circulation line 21b.

[0043] The third switching valve 43 is located in the inlet line 21c. The third switching valve 43 opens and closes the inlet line 21c.

[0044] The fourth switching valve 44 is provided in the first forced circulation line 31a. The fourth switching valve 44 opens and closes the first forced circulation line 31a.

[0045] The fifth switching valve 45 is located near tank 34 in the second forced circulation line 31b. The fifth switching valve 45 opens and closes the second forced circulation line 31b.

[0046] The sixth switching valve 46 is arranged on both an upstream and a downstream side of the pump 35 on the pump line 37. The sixth switching valve 46 opens and closes the pump line 37. (Supply section)

[0047] The storage section 50 is designed to accommodate volume changes in the refrigerant R circulating in the cooling system 1 caused by thermal expansion. The storage section 50 has a reservoir pipe 51 and a storage valve 52.

[0048] The storage pipe 51 extends in the up-down direction Dv and connects an upper end section and a lower end section of the second natural circulation line 21b. A connecting section between an upper end section of the storage pipe 51 and the second natural circulation line 21b is located above the inlet pipe 21c. A connecting section between a lower end section of the storage pipe 51 and the second natural circulation line 21b is located above the tank 34 and below the second switching valve 42. The storage valve 52 is provided at the upper and lower end sections of the storage pipe 51. By actuating one of the storage valves 52 to open the storage pipe 51, a portion of the refrigerant R can be recovered to compensate for the volume change of the refrigerant R caused by thermal expansion. (Transit)

[0049] Passage 60 is located above the first heat exchanger 22. Passage 60 extends in the upward-downward direction Dv. Passage 60 has an internal exhaust air flow path 61 that carries the air A from bottom to top. An inlet opening section 61a, through which the air A is introduced, is provided at a lower end section of the exhaust air flow path 61. An outlet opening section 61b, through which the air A, having flowed through the exhaust air flow path 61, is expelled, is provided at an upper end section of the exhaust air flow path 61.

[0050] The passage 60 has a passage inlet section 62, a passage main body 63, and a passage outlet section 64. The passage inlet section 62 introduces the air A from below into the exhaust gas flow path 61. The passage inlet section 62 has the shape of a bell, extending in the upward-downward direction Dv and decreasing in diameter towards the top. The passage main body 63 has a cylindrical shape, extending upward from an upper end section of the passage inlet section 62. The passage main body 63 is connected to the passage inlet section 62. The passage outlet section 64 is provided at an upper end section of the passage main body 63. The passage outlet section 64 has a cylindrical shape, curved in the horizontal direction as it extends upward from the passage main body 63. The passage outlet section 64 is connected to the passage main body 63.The exhaust gas flow path 61 is formed by the inlet section 62, the main body 63, and the outlet section 64. An opening at a lower end section of the main body 63 is the inlet section 61a of the exhaust gas flow path 61. An opening at an upper end of the outlet section 64 is horizontally oriented. The opening at the upper end of the outlet section 64 is the outlet section 61b of the exhaust gas flow path 61. (Sensor)

[0051] Sensor 4 detects the amount of heat generated by each server rack 2. Information about the amount of heat generated by each server rack 2, detected by Sensor 4, is sent to the control unit 70. In a case where the cooling system 1 is introduced into a server center, as in the present embodiment, for example, a smart power distribution unit (PDU) is used as Sensor 4. The smart PDU monitors a current value for each server rack 2 to detect the total heat generated by each server rack 2.

[0052] Sensor 4 can detect the amount of heat generated for each heat-generating body 3c. (Control unit)

[0053] The control unit 70 controls the operation of the individual configurations of the cooling system 1.

[0054] As in Fig. As shown in Figure 4, the control unit 70 has each of the functional sections of a receiving section 71, a heat generation temperature determination section 72 and a control section 73.

[0055] The recording section 71 receives temperature information and the like to be transmitted from sensor 4.

[0056] From the temperature information received by the recording section 71, the heat generation temperature determination section 72 determines whether a heat generation temperature of the heat generating body 3c is equal to or greater than a threshold value or not.

[0057] Control section 73 controls various devices that make up cooling system 1. Control section 73 also includes a switching control section 73a and a pump control section 73b.

[0058] The switching control section 73a controls the switching section 40 to switch the flow system 6 for the refrigerant R.

[0059] The pump control section 73b controls the pump 35. (Method for operating the cooling system)

[0060] An example of a method for operating the cooling system 1 according to the present embodiment is described.

[0061] As in Fig. As shown in Figure 5, the switching control section 73a controls the switching section 40 to pre-switch the refrigerant R flow system 6 to the natural circulation line 21.

[0062] Fig. Figure 5 shows a state in which the refrigerant flow system 6 is connected to the natural circulation line 21. Fig. 5 is represented by a solid line as a line opened by switching section 40, and by a dashed line as a line closed by switching section 40.

[0063] In this case, the switching control section 73a opens the first switching valve 41, the second switching valve 42, and the third switching valve 43. Accordingly, the natural circulation line 21 is opened, and the refrigerant R can flow through the natural circulation line 21. Furthermore, the switching control section 73a closes the fourth switching valve 44, the fifth switching valve 45, and the sixth switching valve 46. Accordingly, the forced circulation line 31 is opened, and the refrigerant R cannot flow through the forced circulation line 31.

[0064] Subsequently, when the heat-generating body 3c is operated, it generates heat, and heat exchange between the refrigerant R and the heat-generating body 3c is initiated in the cooling device 11. Accordingly, the heat-generating body 3c is cooled, and the refrigerant R is heated by the waste heat from the heat-generating body 3c. When the refrigerant R is heated in the cooling device 11, it boils, and its density decreases. This phenomenon occurs in each cooling device 11. Consequently, an upward flow is generated from the cooling unit 10 towards the first heat exchanger 22. Thus, the refrigerant R, which is subject to heat exchange with the heat-generating body 3c in each cooling device 11, is conveyed to the first heat exchanger 22 via the first natural circulation line 21a.

[0065] Air A is supplied to the first heat exchanger 22 by the blower 23. The first heat exchanger 22 performs the heat exchange between the refrigerant R and the outside air A, transferring the heat from the refrigerant R to the air A. The air A, heated by the waste heat from the refrigerant, is discharged to the outside via the exhaust air flow path 61 in passage 60.

[0066] On the other hand, the refrigerant R is cooled in the first heat exchanger 22, and its density increases. Accordingly, the refrigerant R is distributed from the first heat exchanger 22 via the second natural circulation line 21b and the inlet line 21c to each cooling device 11.

[0067] In this way, the refrigerant R circulates naturally in the natural circulation section 20 by utilizing the waste heat from the heat-generating body 3c. Accordingly, the heat-generating body 3c is always cooled during operation.

[0068] In this case, where the cooling capacity of the first heat exchanger 22 is insufficient for the amount of heat generated, the refrigerant R in the cooling device 11 is completely evaporated, while the refrigerant R circulates in the natural circulation section 20, and thus the heat generating unit 3c cannot be adequately cooled. To prevent such a situation, the cooling system 1 in the present embodiment has a function for switching the flow system 6 of the refrigerant R from the natural circulation line 21 to the forced circulation line 31 via the switching section 40. (Method for switching the flow system)

[0069] Next, a method for switching the refrigerant R flow system 6 according to the present embodiment is described with reference to the Fig. 5 to 7 described.

[0070] Fig. Figure 6 shows the sequence of the procedure for switching the flow system 6 of the refrigerant R.

[0071] Fig. Figure 7 shows a state in which the refrigerant flow system 6 is switched to the forced circulation line 31. Fig. 7 is represented by a solid line as a line opened by switching section 40, and by a dashed line as a line closed by switching section 40.

[0072] The temperature of the heat-generating body 3c is continuously or periodically measured by sensor 4. Sensor 4 periodically transmits the measured temperature to control unit 70.

[0073] As in Fig. As shown in Figure 6, the receiving section 71 first receives the temperature of the heat-generating body 3c (step S11). After step S11, the heat-generating temperature determination section 72 determines whether the temperature of the heat-generating body 3c is equal to or greater than the threshold value (step S12). This threshold value is preset in the control unit 70. If the temperature of the heat-generating body 3c is equal to or greater than the threshold value (YES in step S12), the cooling capacity of the first heat exchanger 22 of the natural circulation section 20 is insufficient for the amount of heat generated.

[0074] Therefore, in the next step, it is necessary to switch the system so that the refrigerant R is cooled by the second heat exchanger 36, which has a larger capacity than the first heat exchanger 22. First, the switching control section 73a controls the switching section 40 to switch the refrigerant R flow system 6 from the natural circulation line 21 to the forced circulation line 31, as shown in Fig. Figure 7 shows (step S13). In step S13, the switching control section 73a closes the first switching valve 41, the second switching valve 42, and the third switching valve 43 to block the natural circulation line 21. Furthermore, the switching control section 73a opens the fourth switching valve 44, the fifth switching valve 45, and the sixth switching valve 46 to open the forced circulation line 31.

[0075] After step S13, the pump control section 73b drives the pump 35 (step S14). Accordingly, the forced circulation section 30 is operated, and the refrigerant R circulates in the forced circulation section 30 to be cooled by the second heat exchanger 36, which has a larger capacity than the first heat exchanger 22. If the forced circulation line 31 is already opened in step S12, steps S13 and S14 are omitted.

[0076] On the other hand, in a case where the temperature of the heat-generating body 3c is not equal to or greater than the threshold (No in step S12), the cooling capacity of the first heat exchanger 22 of the natural circulation section 20 is sufficient for the amount of heat generated.

[0077] Therefore, in the next step, it is necessary to switch the refrigerant R through the first heat exchanger 22, which has a small capacity, and on to the second heat exchanger 36, which has a large capacity, in order to limit operating energy. First, the pump control section 73b stops the pump 35 (step S15). After step S15, the switching control section 73a controls the switching section 40 to switch the refrigerant R flow system 6 from the forced circulation line 31 to the natural circulation line 21 (step S16). In step S16, the switching control section 73a closes the fourth switching valve 44, the fifth switching valve 45, and the sixth switching valve 46 to shut off the forced circulation line 31. Furthermore, the switching control section 73a opens the first switching valve 41, the second switching valve 42 and the third switching valve 43 to open the natural circulation line 21.In a case where the natural circulation line 21 is already open in step S12, steps S15 and S16 are omitted.

[0078] In the above procedure, the refrigerant flow system 6 is switched. This switching of the refrigerant flow system 6 is performed each time the receiving section 71 receives the temperature of the heat-generating body 3c.

[0079] In step S13, the natural circulation line 21 is closed and the forced circulation line 31 is opened, but the present invention is not limited to this. In step S13, both the natural circulation line 21 and the forced circulation line 31 can be opened, so that the refrigerant R flows through both the natural circulation line 21 and the forced circulation line 31. In this case, it is possible to cool the refrigerant R through both the first heat exchanger 22 and the second heat exchanger 36. (Mode of action)

[0080] The cooling system 1 according to the present embodiment can exert the following effects.

[0081] In the present embodiment, the cooling system 1 comprises the cooling unit 10, the natural circulation section 20, and the forced circulation section 30. The cooling unit 10 has a plurality of cooling devices 11, the inlet-side distributor 12, and the outlet-side distributor 15. The multiple cooling devices 11 cool the heat-generating body 3c. The inlet-side distributor 12 distributes the refrigerant R to the cooling devices 11. The refrigerant R is directed from each cooling device 11 to the outlet-side distributor 15. The natural circulation section 20 has the natural circulation line 21 and the first heat exchanger 22. The natural circulation line 21 connects the outlet-side distributor 15 and the inlet-side distributor 12. The first heat exchanger 22 is located in the middle of the natural circulation line 21 and above the cooling unit 10.The forced circulation section 30 consists of the forced circulation line 31, the second heat exchanger 36, and the pump 35. The forced circulation line 31 connects the outlet distributor 15 and the inlet distributor 12. The second heat exchanger 36 is located in the middle of the forced circulation line 31. The second heat exchanger 36 has a larger capacity than the first heat exchanger 22. The pump 35 is located in the forced circulation line 31. The pump 35 pumps the refrigerant R from the outlet distributor 15 towards the inlet distributor 12.

[0082] With the configuration described above, each cooling device 11 performs heat exchange between the heat-generating body 3c and the refrigerant R to cool the heat-generating body 3c. Conversely, the refrigerant R is heated by the heat generated by the heat-generating body 3c. Consequently, the density of the refrigerant R decreases, and the refrigerant R flows upwards. The natural circulation section 20 utilizes this flow to initiate natural circulation of the refrigerant R. In the natural circulation section 20, the refrigerant R, which is undergoing heat exchange with the heat-generating body 3c, is cooled by the first heat exchanger 22 and returned to the heat-generating body 3c. Furthermore, in the forced circulation section 30, the refrigerant R is forcibly circulated by the pumping force of the pump 35.In the forced circulation section 30, the refrigerant R pumped by the pump 35 is subjected to heat exchange by the heat generator 3c, cooled by the second heat exchanger 36, and returned to the heat generator 3c. As described above, the refrigerant R is cooled by the first heat exchanger 22 in the natural circulation section 20, and the refrigerant R is cooled by the second heat exchanger 36 in the forced circulation section 30. Since the capacity of the second heat exchanger 36 is greater than that of the first heat exchanger 22, it is possible to cool the refrigerant R sufficiently in the second heat exchanger 36 using the forced circulation section 30, even if the cooling capacity of the first heat exchanger 22 of the natural circulation section 20 is insufficient.

[0083] In this way, it is possible to cool the heat-generating body 3c with good energy efficiency and at the same time to cool the heat-generating body 3c sufficiently in every temperature zone. Therefore, according to the present embodiment, it is possible to improve the cooling efficiency of the cooling system 1 while simultaneously ensuring sufficient cooling capacity.

[0084] Furthermore, the cooling system 1 includes the switching section 40. The switching section 40 switches the refrigerant R flow system 6 to at least one of the natural circulation line 21 and the forced circulation line 31.

[0085] Accordingly, if the heat-generating body 3c can be sufficiently cooled by the cooling capacity of the first heat exchanger 22, the refrigerant flow system 6 can be switched to the natural circulation line 21. Therefore, it is possible to cool the refrigerant R, which is subject to heat exchange with the heat-generating body 3c, using only the first heat exchanger 22. Since only the first heat exchanger 22 is used, it is possible to reduce the amount of energy required to operate the cooling system 1. Conversely, if the cooling capacity of the first heat exchanger 22 is insufficient for the amount of heat generated, the refrigerant flow system 6 can be switched to the forced circulation line 31, or to both the natural circulation line 21 and the forced circulation line 31.Since the refrigerant R, which is subject to heat exchange with the heat-generating body 3c, can be cooled by using the second heat exchanger 36 with a larger capacity than the first heat exchanger 22, it is possible to cool the refrigerant R sufficiently.

[0086] In this way, it is possible to circulate the refrigerant R by switching between the natural circulation line 21 and the forced circulation line 31 according to the amount of heat generated. Therefore, according to the present embodiment, it is possible to further improve the cooling efficiency of the cooling system 1.

[0087] Furthermore, the second heat exchanger 36 is located below the cooling unit 10.

[0088] In the forced circulation section 30, the refrigerant R circulates primarily due to the pumping action of the pump 35. Thus, the refrigerant R supplied to the second heat exchanger 36 is directed into the second heat exchanger 36 before it completely evaporates. Consequently, the density of the refrigerant R supplied to the second heat exchanger 36 is higher than the density of the refrigerant R supplied to the first heat exchanger 22. A refrigerant R with a higher density is likely to accumulate at the bottom. Therefore, by arranging the second heat exchanger 36 below the cooling unit 10, as in the present embodiment, the refrigerant R can be supplied to the second heat exchanger 36 more easily. Since the second heat exchanger 36 can cool the refrigerant R more efficiently, it is possible to further improve the cooling efficiency of the cooling system 1.

[0089] Furthermore, the natural circulation line 21 has the inlet line 21c for introducing the refrigerant R, which is subjected to heat exchange in the first heat exchanger 22, into the inlet-side distributor 12. The inlet line 21c is arranged above the majority of the cooling units 11. The pump 35 is arranged below the majority of the cooling units 11.

[0090] As described above, in the present embodiment the inlet line 21c is arranged above the majority of cooling devices 11. This allows the length of the flow path of the natural circulation section 20 to be shortened. Therefore, it is possible to limit the pressure loss in a case where the refrigerant R is caused to circulate naturally.

[0091] On the other hand, the refrigerant R, whose density increases upon cooling, is supplied to the pump 35. The high-density refrigerant R is likely to sink. By arranging the pump 35 below the multiple cooling devices 11, as in the present embodiment, the refrigerant R can be easily supplied to the pump 35. Accordingly, it is possible to route the refrigerant R from the pump 35 to each cooling device 11.

[0092] Therefore, it is possible to allow the refrigerant R to circulate easily in both the natural circulation section 20 and the forced circulation section 30, thus further improving the cooling efficiency of the cooling system 1.

[0093] Furthermore, the forced circulation section 30 has a plurality of pumps 35 in the forced circulation line 31.

[0094] Accordingly, it is possible, for example, to continue circulating the refrigerant R continuously with other pumps 35 even if one of the several pumps 35 unexpectedly stops operating. In this way, it is possible to provide redundancy to the forced circulation section 30.

[0095] Furthermore, the cooling system 1 includes a passage 60 located above the first heat exchanger 22. The passage 60 extends in the upward-downward direction Dv and has the internal exhaust airflow path 61, which carries the air A away from bottom to top.

[0096] The air A in the vicinity of the first heat exchanger 22 is heated by utilizing the waste heat of the refrigerant R. The high-temperature air A, heated by the first heat exchanger 22, is directed into passage 60. Consequently, the air A in passage 60 has a higher temperature and a lower density than the air A outside passage 60, resulting in a draft (chimney effect). The air A flows from below passage 60 to above it. This allows the air A to be easily drawn into the first heat exchanger 22, thus promoting the cooling of the refrigerant R by the first heat exchanger 22. Therefore, the cooling capacity of the cooling system 1 is improved.

[0097] Furthermore, it is possible to reduce the delivery force, e.g., of the blower 23, which supplies air to the first heat exchanger 22, required to supply the air A to the first heat exchanger. In the case of a low load, where the load on the heat-generating body 3c is low, the amount of heat generated is small, and thus it is also possible to supply the air A to the first heat exchanger 22 in sufficient quantity via the airflow A due to the draft effect of the passage 60. In this case, the blower 23 can be switched off. Since the refrigerant R can be cooled in this way with high energy efficiency, it is possible to further improve the cooling efficiency of the cooling system 1.

[0098] Furthermore, the passage 60 has the passage inlet section 62, which introduces the air A from below into the exhaust gas flow path 61 and has the shape of a bell whose diameter decreases towards the top.

[0099] Accordingly, it is possible to cause passage 60 to introduce the air A evenly into the exhaust gas flow path 61. This makes it possible to reduce the pressure loss when introducing the air A.

[0100] Furthermore, the first heat exchanger 22 is installed such that the inlet section 25a is located above the outlet section 25b.

[0101] Accordingly, the refrigerant R flows easily and evenly through the first heat exchanger 22 from the supply section 25a to the outlet section 25b. Therefore, it is possible to circulate the refrigerant R efficiently in the natural circulation section 20 and thus further improve the cooling efficiency of the cooling system 1.

[0102] Next, a modification example of the first embodiment is described. The same reference numbers and names are assigned to the same configurations as in the first embodiment described above, and their descriptions are omitted where necessary. Configurations not described below are assumed to be identical to those of the first embodiment. <Erstes Modifikationsbeispiel der ersten Ausführungsform>

[0103] A first modification example of the first embodiment is described with reference to Fig. 8 below.

[0104] A cooling system 1A of the present modification example comprises the server rack 2, the server 3, the cooling unit 10, a natural circulation section 20A, the forced circulation section 30, the switching section 40, the reservoir section 50, the passage 60, the sensor 4, and the control unit 70. The natural circulation section 20A has a natural circulation line 21A, the first heat exchanger 22, the fan 23, and the relief valve 24. The natural circulation line 21A has the first natural circulation line 21a, the second natural circulation line 21b, and an inlet line 21Ac.

[0105] As in Fig. As shown in Figure 8, the inlet line 21Ac is arranged below the plurality of cooling devices 11. A connecting section between the inlet line 21Ac and the second natural circulation line 21b is arranged above the tank 34 and below the second switching valve 42 and the storage valve 52 on the down side Dvd. A connecting section between the inlet line 21Ac and the inlet-side distributor 12 is arranged below the multiple cooling devices 11. (Mode of action)

[0106] The cooling system 1A of the present modification example can have the following effects.

[0107] In the present modification example, the inlet line 21Ac is arranged below the majority of cooling devices 11.

[0108] The refrigerant R, whose density is increased by cooling through the first heat exchanger 22, is fed into the inlet line 21Ac. The high-density refrigerant R is likely to sink. By arranging the inlet line 21Ac below the plurality of cooling devices 11, as in the present embodiment, the refrigerant R can be easily fed into the inlet line 21Ac. Accordingly, it is possible to supply the refrigerant R stably from the inlet line 21Ac to each cooling device 11. Therefore, it is possible to cause the refrigerant R to circulate easily in the natural circulation section 20A, thus further improving the cooling efficiency of the cooling system 1A. <Zweites Modifikationsbeispiel der ersten Ausführungsform>

[0109] Next, a second modification example of the first embodiment will be described with reference to Fig. 9 and Fig. 10 described.

[0110] A cooling system 1B of the present modification example comprises the server rack 2, the server 3, the cooling unit 10, a natural circulation section 20B, the forced circulation section 30, the switching section 40, the reservoir section 50, the passage 60, the sensor 4, and the control unit 70. The natural circulation section 20B has the natural circulation line 21, a first heat exchanger 22B, the connection section 26, the fan 23, and the pressure relief valve 24.

[0111] As in Fig. 9 and Fig. As shown in Figure 10, four first heat exchangers 22B are arranged on the upper plate 2a of the frame.

[0112] In the Fig. 9 and Fig. 10 is part of the configuration, such as the natural circulation line 21, which carries the refrigerant R through each first heat exchanger 22B, not shown.

[0113] The four first heat exchangers 22B are arranged to surround an edge of the upper plate 2a. A first heat exchanger 22B is provided individually for each edge of the upper plate 2a. The first heat exchanger 22B of the present modified embodiment is the same radiator 25 as in the first embodiment. Each first heat exchanger 22B has an inlet section 25a and an outlet section 25b. Each first heat exchanger 22B is installed such that the inlet section 25a is located above the outlet section 25b. The outlet section 25b is positioned along the edge of the upper plate 2a.

[0114] The connecting section 26 is provided between two adjacent first heat exchangers 22B to fill a gap between them. Each connecting section 26 connects adjacent first heat exchangers. (Mode of action)

[0115] The cooling system 1B of the present modification example can exert the following effects.

[0116] In the present modification example, the majority of the first heat exchangers 22B are arranged such that they surround the edge of the upper plate 2a. The first heat exchanger 22B is provided one after the other for each edge of the upper plate 2a.

[0117] In this way it is possible to place a large number of first heat exchangers 22B on server rack 2 without obstructing the airflow A. <Zweite Ausführungsform>

[0118] Next, a second embodiment will be described with reference to the Fig. Sections 11 to 13 describe the same configurations. The same reference numbers and names are assigned to the same configurations as in the embodiments and modification examples above, and their descriptions are omitted where necessary. Configurations not described below are assumed to be the same as those in the embodiments and modification examples above. (Cooling system)

[0119] In the present embodiment, a cooling system 101 comprises the server rack 2, the server 3, the cooling unit 10, a natural circulation section 120, a forced circulation section 130, a switching section 140, the sensor 4 and a control unit 170. (Server rack)

[0120] Server rack 2 is the same enclosure, extending in the up-down direction Dv as in the first embodiment (see Fig. 2). (Server)

[0121] The majority of the servers 3 are arranged in the server rack 2 in the vertical direction Dv. Each server 3 has a housing 3a, a server board 3b, and a heat sink 3c. The housing 3a is inserted transversely in the horizontal direction into the server rack 2. The server board 3b and the heat sink 3c are located inside the housing 3a. The server board 3b extends horizontally. The heat sink 3c is attached to the server board 3b in the same manner as in the first embodiment. (Cooling unit)

[0122] As in Fig. As shown in Figure 11, the cooling unit 10 has a plurality of cooling devices 11, the inlet-side distributor 12, and the outlet-side distributor 15. The multiple cooling devices 11 cool the heat-generating body 3c. The cooling device 11 of the present embodiment is the same cold plate 11a as in the first embodiment. The inlet-side distributor 12 distributes the refrigerant R to the cooling devices 11. The refrigerant R is discharged from each cooling device 11 to the outlet-side distributor 15. (Section with natural circulation)

[0123] The natural circulation section 120 has a natural circulation line 121, the first heat exchanger 22, the blower 23 and a distributor 27.

[0124] The natural circulation line 121 connects the outlet-side distributor 15 and the inlet-side distributor 12. The first heat exchanger 22 is installed in the middle of the natural circulation line 121 and above the cooling unit 10. Furthermore, the distributor 27 is located in the middle of the natural circulation line 121, downstream of and below the first heat exchanger 22. Each configuration of the natural circulation section 120 is described in detail below.

[0125] The natural circulation line 121 has a first natural circulation line 121a, a second natural circulation line 121b, and an inlet line 121c. The first natural circulation line 121a connects the upper end section of the outlet-side distributor 15 and the first heat exchanger 22. The first natural circulation line 121a carries the refrigerant R from the outlet-side distributor 15 to the first heat exchanger 22. The heat exchange of the refrigerant R takes place in the first heat exchanger 22. The second natural circulation line 121b extends downwards from the first heat exchanger 22.

[0126] The inlet line 121c is a bypass line that bypasses the second natural circulation line 121b. The inlet line 121c is located downstream and below the distributor 27. Furthermore, the inlet line 121c is located above the plurality of cooling devices 11. The refrigerant R, which undergoes heat exchange in the first heat exchanger 22, is temporarily stored in the distributor 27 and then fed to the inlet line 121c via the second natural circulation line 121b. The inlet line 121c introduces the refrigerant R, which is undergoing heat exchange in the first heat exchanger 22, into the inlet-side distributor 12.

[0127] The first heat exchanger 22 cools the refrigerant R, which undergoes heat exchange with the heat-generating element 3c in the cooling device 11. The cooling device 11 of the present embodiment is the same air cooler 25 as in the first embodiment.

[0128] The distributor 27 can temporarily store the refrigerant R cooled by the first heat exchanger 22. (Section on forced circulation)

[0129] The forced circulation section 130 is a mechanism that circulates the refrigerant R independently of the refrigerant R being heated by the waste heat from the heat-generating unit 3c. The forced circulation section 130 has a forced circulation line 131 and a pump 35. The forced circulation line 131 connects the downstream side of the first heat exchanger 22 of the natural circulation line 121 and the inlet-side distributor 12. Furthermore, the pump 35 is located on the downstream side of the second heat exchanger 36 on the forced circulation line 131. Each configuration of the forced circulation section 130 is described in detail below.

[0130] The forced circulation line 131 connects a lower end of the second natural circulation line 121b and a lower end of the inlet-side distributor 12. The forced circulation line 131 is supplied with the refrigerant R, which is cooled by the first heat exchanger 22 and then temporarily stored in the distributor 27. The forced circulation line 131 conveys the cooled refrigerant R to the inlet-side distributor 12.

[0131] Pump 35 pumps the refrigerant R from the outlet distributor 15 to the inlet distributor 12. The refrigerant R pumped by pump 35 is distributed from the inlet distributor to each cooling device 11 to circulate in the cooling system 101. Pump 35 is located below the plurality of cooling devices 11. (Switching section)

[0132] The switching section 140 has a first switching valve 141 and a second switching valve 142.

[0133] The first switching valve 141 is located in the inlet line 121c. The first switching valve 141 opens and closes the inlet line 121c.

[0134] The second switching valve 142 is located in the forced circulation line 131 and between the pump 35 and the inlet-side distributor 12. The second switching valve 142 opens and closes the forced circulation line 131. (Sensor)

[0135] Sensor 4 detects the amount of heat generated for each server rack 2 in the same way as in the first embodiment. Sensor 4 can detect the amount of heat generated for each heat-generating element 3c. (Control unit)

[0136] The control unit 170 controls the operation of the individual configurations of the cooling system 101.

[0137] As in Fig. As shown in Figure 12, the control unit 170 has each of the functional sections of a receiving section 171, a heat generation temperature determination section 172 and a control section 173.

[0138] The recording section 171 receives temperature information and the like to be transmitted from sensor 4.

[0139] From the temperature information received by the receiving section 171, the heat generation temperature determination section 172 determines whether a heat generation temperature of the heat-generating body 3c is equal to or greater than a threshold value or not.

[0140] Control section 173 controls various devices that make up the cooling system 101. Control section 173 also includes a switching control section 173a and a pump control section 173b.

[0141] The switching control section 173a controls the switching section 140 to switch a refrigerant flow system 106. The flow system 106 is a flow path through which the refrigerant R flows and includes the natural circulation line 121 and the forced circulation line 131.

[0142] The pump control section 173b controls the pump 35. (Method for operating the cooling system)

[0143] An example of a method for operating the cooling system 101 according to the present embodiment is described.

[0144] The switching control section 173a controls the switching section 140 to pre-switch the refrigerant R flow system 106 to the natural circulation line 121.

[0145] In this case, the switching control section 173a opens the first switching valve 141. Accordingly, the natural circulation line 121 is opened, and the refrigerant R can flow through the natural circulation line 121. Furthermore, the switching control section 173a closes the second switching valve 142. Accordingly, the forced circulation line 131 is opened, and the refrigerant R cannot flow through the forced circulation line 131.

[0146] Subsequently, in the case where the heat-generating body 3c is operating, the heat-generating body 3c generates heat, and the heat exchange between the refrigerant R and the heat-generating body 3c is initiated in the cooling device 11. Accordingly, the heat-generating body 3c is cooled, and the refrigerant R is heated by the waste heat from the heat-generating body 3c. When the refrigerant R is heated in the cooling device 11, it boils, and its density decreases. This phenomenon occurs in each cooling device 11. Consequently, an upward flow is generated from the cooling unit 10 towards the first heat exchanger 22. Therefore, the refrigerant R, which is subject to heat exchange with the heat-generating body 3c in each cooling device 11, is conveyed to the first heat exchanger 22 via the first natural circulation line 121a.

[0147] Air A is supplied to the first heat exchanger 22 by the blower 23. The first heat exchanger 22 carries out the heat exchange between the refrigerant R and the outside air A and transfers the heat from the refrigerant R to the air A.

[0148] On the other hand, the refrigerant R is cooled in the first heat exchanger 22, and its density increases. Accordingly, the refrigerant R is distributed from the first heat exchanger 22 to each cooling device 11 via the second natural circulation line 121b and the inlet line 121c.

[0149] In this way, the refrigerant R circulates naturally within the area of ​​natural circulation 120, utilizing the waste heat from the heat-generating body 3c. Accordingly, the heat-generating body 3c is always cooled during operation.

[0150] In this case, where the cooling capacity of the first heat exchanger 22 is insufficient for the amount of heat generated, the refrigerant R in the cooling device 11 is completely evaporated, while the refrigerant R circulates in the natural circulation section 120, and thus the heat generating unit 3c cannot be adequately cooled. To prevent such a situation, the cooling system 101 in the present embodiment has a function for switching the flow system 106 of the refrigerant R from the natural circulation line 121 to the forced circulation line 131 via the switching section 140. (Method for switching the flow system)

[0151] Next, a method for switching the refrigerant R flow system 106 according to the present embodiment is described with reference to Fig. 13 described.

[0152] Fig. 13 is a sequence of the procedure for switching the flow system 106 of the refrigerant R.

[0153] The temperature of the heat-generating body 3c is continuously or periodically measured by sensor 4. Sensor 4 periodically transmits the measured temperature to control unit 170.

[0154] As in Fig. As shown in Figure 13, the receiving section 171 first receives the temperature of the heat-generating body 3c (step S21). After step S21, the heat-generating temperature determination section 172 determines whether the temperature of the heat-generating body 3c is equal to or greater than the threshold value (step S22). This threshold value is preset in the control unit 170. If the temperature of the heat-generating body 3c is equal to or greater than the threshold value (YES in step S22), the cooling capacity of the first heat exchanger 22 of the natural circulation section 120 is insufficient for the amount of heat generated.

[0155] Therefore, in the next step, it is necessary to switch the system so that pump 35 pumps the refrigerant R to increase the refrigerant R flow rate. First, the switching control section 173a controls the switching section 140 to switch the refrigerant R flow system 106 from the natural circulation line 121 to the forced circulation line 131, as shown in Fig. Figure 13 shows (step S23). In step S23, the switching control section 173a closes the first switching valve 141 to block the natural circulation line 121. Furthermore, the switching control section 173a opens the second switching valve 142 to open the forced circulation line 131.

[0156] After step S13, the pump control section 173b drives the pump 35 (step S24). Accordingly, the forced circulation section 130 is operated, and the refrigerant R circulates in the forced circulation section 130 to be supplied to each cooling device 11 from below. If the forced circulation line 131 is already opened in step S22, steps S23 and S24 are omitted.

[0157] On the other hand, in a case where the temperature of the heat-generating body 3c is not equal to or greater than the threshold (No in step S22), the cooling capacity of the first heat exchanger 22 of the natural circulation section 120 is sufficient for the amount of heat generated.

[0158] In the next step, it is therefore necessary to switch the system so that the refrigerant R circulates in the natural circulation section 120, where pump 35 does not need to be operated, thus limiting operating energy. First, pump control section 173b stops pump 35 (step S25). After step S25, switching control section 173a controls switching section 140 to switch the refrigerant R flow system 106 from forced circulation line 131 to natural circulation line 121 (step S26). In step S26, switching control section 173a closes the second switching valve 142 to block forced circulation line 131. Furthermore, switching control section 173a opens the first switching valve 141 to open natural circulation line 121. In a case where the natural circulation line 121 is already open in step S22, steps S25 and S26 are omitted.

[0159] In the above procedure, the refrigerant R flow system 106 is switched. The refrigerant R in the flow system 106 is switched each time the receiving section 171 receives the temperature of the heat-generating body 3c.

[0160] In step S23, the natural circulation line 121 is closed and the forced circulation line 131 is opened, but the present invention is not limited to this. In step S23, both the natural circulation line 121 and the forced circulation line 131 can be opened, so that the refrigerant R flows through both the natural circulation line 121 and the forced circulation line 131. (Mode of action)

[0161] The cooling system 101 of the present embodiment can exert the following effects.

[0162] In the present embodiment, the natural circulation line 121 has the inlet line 121c for introducing the refrigerant R, which is subjected to heat exchange in the first heat exchanger 22, into the inlet-side distributor 12. The inlet line 121c is arranged above the majority of the cooling units 11. The pump 35 is arranged below the majority of the cooling units 11.

[0163] As described above, in the present embodiment the inlet line 121c is arranged above the majority of cooling devices 11. This allows the length of the flow path of the natural circulation section 120 to be shortened. Therefore, it is possible to limit the pressure loss in a case where the refrigerant R is caused to circulate naturally.

[0164] On the other hand, the refrigerant R, whose density increases upon cooling, is supplied to the pump 35. The high-density refrigerant R is likely to sink. By arranging the pump 35 below the multiple cooling devices 11, as in the present embodiment, the refrigerant R can be easily supplied to the pump 35. Accordingly, it is possible to route the refrigerant R from the pump 35 to each cooling device 11.

[0165] Therefore, it is possible to allow the refrigerant R to circulate easily in both the natural circulation section 120 and the forced circulation section 130, thus further improving the cooling efficiency of the cooling system 101.

[0166] Next, a modification example of the second embodiment is described. The same configurations as in the second embodiment described above are assigned the same reference numbers and names, and their descriptions are omitted where necessary. Configurations not described below are assumed to be identical to those of the second embodiment. <Erstes Modifikationsbeispiel der zweiten Ausführungsform>

[0167] A first modification example of the second embodiment is given with reference to Fig. 14 described.

[0168] In addition to the server rack 2, the server 3, the cooling unit 10, the natural circulation section 120, the forced circulation section 130, the switching section 140, the sensor 4 and the control unit 170, a cooling system 101A of the present modification example includes passage 60. (Transit)

[0169] The passage 60 is located above the first heat exchanger 22. The passage 60 extends in the upward-downward direction Dv. The passage 60 has an internal exhaust air flow path 61 that carries the air A from bottom to top. The inlet opening section 61a, through which the air A is introduced, is located at the lower end of the exhaust air flow path 61. The outlet opening section 61b, through which the air A, having flowed through the exhaust air flow path 61, is expelled, is located at the upper end of the exhaust air flow path 61.

[0170] The passage 60 of the present embodiment is designed in the same form as in the first embodiment. That is, the passage 60 has the passage inlet section 62, the passage main body 63, and the passage outlet section 64. The passage inlet section 62 has the shape of a bell that extends in the upward-downward direction Dv and decreases in diameter upwards. (Mode of action)

[0171] The cooling system 101A of the present modification example can exert the following effects.

[0172] The cooling system 101A of the present modification example further comprises the passage 60, which is arranged above the first heat exchanger 22. The passage 60 extends in the upward-downward direction Dv and has the internal exhaust gas flow path 61, which carries the air A away from bottom to top.

[0173] The air A surrounding the first heat exchanger 22 is heated by the waste heat of the refrigerant R. The high-temperature air A, heated by the first heat exchanger 22, is directed into passage 60. Consequently, the air A in passage 60 has a higher temperature and a lower density than the air A outside passage 60, resulting in a draft effect (chimney effect). The air A flows from below passage 60 to above it. This allows the air A to easily reach the first heat exchanger 22, thus promoting the cooling of the refrigerant R by the first heat exchanger 22. Therefore, the cooling efficiency of the cooling system 101A is improved.

[0174] Furthermore, it is possible to reduce the delivery power of, for example, the blower 23, which supplies air to the first heat exchanger 22, which is necessary to deliver the air A to the first heat exchanger. In the case of a low load, where the load on the heat-generating body 3c is low, the amount of heat generated is small, and thus it is also possible to supply the air A to the first heat exchanger 22 in sufficient quantity via the airflow A due to the draft effect of the passage 60. In this case, the blower 23 can be switched off. Since the refrigerant R can be cooled with high efficiency, it is possible in this way to further improve the cooling efficiency of the cooling system 101A. <Zweites Modifikationsbeispiel der zweiten Ausführungsform>

[0175] Next, a second modification example of the second embodiment will be presented with reference to Fig. 15 described.

[0176] As in Fig. As shown in Figure 15, a cooling system 101B of the present amendment example has a plurality of unit parts 5 and a passage 160. Each unit part 5 further comprises the server rack 2, the server 3, the cooling unit 10, the natural circulation section 120, the forced circulation section 130, the switching section 140, the passage 160, the sensor 4, and the control unit 170. That is to say, in the present amendment example, a cooling system 101B comprises a plurality of cooling units 10, a plurality of natural circulation sections 120 provided for each cooling unit 10, and a plurality of forced circulation sections 130.

[0177] The passage 160 of the present embodiment is arranged above the majority of the unit parts 5. The passage 160 extends in the upward-downward direction Dv. The passage 160 has an internal exhaust air flow path 161, which carries the air A from bottom to top, in the same manner as in the first embodiment. An inlet opening section 161a, through which air A is introduced, is provided at a lower end section of the exhaust air flow path 161. An outlet opening section 161b, through which the air A, which has flowed through the exhaust air flow path 161, is expelled, is provided at an upper end section of the exhaust air flow path 161.

[0178] The passage 160 has a passage inlet section 162, a passage head section 163, and a passage outlet section 164. The passage inlet section 162 is arranged above each of the plurality of first heat exchangers 22 and introduces the air A into the first heat exchangers 22 from below. The passage inlet section 162 of the present modification example has the shape of a bell, extending in the upward-downward direction Dv, with a diameter that decreases upwards, in the same manner as in the first embodiment. The passage head section 163 connects the upper end sections of the plurality of passage inlet sections 162 to combine the air A introduced by each passage inlet section 162. The passage head section 163 is arranged to extend in the horizontal direction.The through-flow outlet section 164 extends upwards from the through-flow head section 163 to expel upwards the air A that has been drawn in through the through-flow head section 163. The through-flow outlet section 164 is cylindrical in shape with a uniform thickness.

[0179] In the present modification example, the exhaust gas flow path 161 is formed by the inlet section 162, the head section 163, and the outlet section 164. An opening at a lower end section of each inlet section 162 is the inlet section 161a of the exhaust gas flow path 161. Furthermore, an opening at an upper end of the outlet section 164 is the outlet section 161b of the exhaust gas flow path 161. (Action effect)

[0180] The cooling system 101B of the present modification example can exert the following effects.

[0181] In the cooling system 101B of the present modification example, a cooling system 101B comprises the plurality of cooling units 10, the plurality of natural circulation sections provided for each cooling unit 10, and the plurality of forced circulation sections 130. Furthermore, the passage 160 has a passage inlet section 162, a passage head section 163, and a passage outlet section 164. The passage inlet section 162 is arranged above each of the multiple first heat exchangers 22 and introduces the air A into the first heat exchangers 22 from below. The passage head section 163 connects the upper end sections of the multiple passage inlet sections 162 to cause the air A introduced by each passage inlet section 162 to be combined.The through-outlet section 164 extends upwards from the through-head section 163 to expel upwards the air A that has been brought together through the through-head section 163.

[0182] With the configuration described above, it is possible to combine the air A heated by the multiple first heat exchangers 22 into a single flow. Accordingly, it is possible to accelerate the flow of air A from below passage 160 to above passage 160. This improves the draft effect of passage 160. Therefore, the air A is more easily supplied to the first heat exchanger 22, and the cooling of the refrigerant R by the first heat exchanger 22 is further enhanced. Consequently, it is possible to further improve the cooling efficiency of the cooling system 101B. In addition, space savings can be achieved. <Dritte Ausführungsform>

[0183] Next, a third embodiment will be described with reference to Fig. 16 and Fig. 17. The same configurations as in the embodiments and modification examples above are assigned the same reference numbers and names, and their descriptions are omitted where necessary. Configurations not described below are assumed to be the same as those in the embodiments and modification examples above. (Cooling system)

[0184] In the present embodiment, a cooling system 201 comprises the server rack 2, the server 3, the cooling unit 10, the natural circulation section 120 and a control unit 270. (Server rack)

[0185] Server rack 2 is the same enclosure, extending in the up-down direction Dv as in the first embodiment (see Fig. 2). (Server)

[0186] The majority of the servers 3 are arranged in the server rack 2 in an up-down orientation Dv. Each server 3 has a housing 3a, a server board 3b, and a heat sink 3c. The housing 3a is inserted transversely in the server rack 2 in a horizontal direction. The server board 3b and the heat sink 3c are located inside the housing 3a. The server board 3b extends horizontally. The heat sink 3c is attached to the server board 3b in the same manner as in the first embodiment. (Cooling unit)

[0187] As in Fig. As shown in Figure 16, the cooling unit 10 has a plurality of cooling devices 11, the inlet-side distributor 12, and the outlet-side distributor 15. The multiple cooling devices 11 cool the heat-generating body 3c. The cooling device 11 of the present embodiment is the same cold plate 11a as in the first embodiment. The inlet-side distributor 12 distributes the refrigerant R to the cooling devices 11. The refrigerant R is discharged from each cooling device 11 to the outlet-side distributor 15. (Section with natural circulation)

[0188] The natural circulation section 120 consists of the natural circulation line 121, the first heat exchanger 22, the blower 23, the distributor 27 and a valve 28.

[0189] The natural circulation line 121 connects the outlet-side distributor 15 and the inlet-side distributor 12. The first heat exchanger 22 is installed in the middle of the natural circulation line 121 and above the cooling unit 10. Furthermore, the distributor 27 is located in the middle of the natural circulation line 121, downstream of and below the first heat exchanger 22. Each configuration of the natural circulation section 120 is described in detail below.

[0190] The natural circulation line 121 has a first natural circulation line 121a, a second natural circulation line 121b, and an inlet line 121c. The first natural circulation line 121a connects the upper end section of the outlet-side distributor 15 and the first heat exchanger 22. The first natural circulation line 121a carries the refrigerant R from the outlet-side distributor 15 to the first heat exchanger 22. The heat exchange of the refrigerant R takes place in the first heat exchanger 22. The second natural circulation line 121b extends downwards from the first heat exchanger 22.

[0191] The inlet line 121c is a bypass line that bypasses the second natural circulation line 121b. The inlet line 121c is located downstream and below the distributor 27. Furthermore, the inlet line 121c is located above the plurality of cooling devices 11. The refrigerant R, which undergoes heat exchange in the first heat exchanger 22, is temporarily stored in the distributor 27 and then fed to the inlet line 121c via the second natural circulation line 121b. The inlet line 121c introduces the refrigerant R, which is undergoing heat exchange in the first heat exchanger 22, into the inlet-side distributor 12.

[0192] The first heat exchanger 22 cools the refrigerant R, which undergoes heat exchange with the heat-generating element 3c in the cooling device 11. The cooling device 11 of the present embodiment is the same air cooler 25 as in the first embodiment.

[0193] For example, a first heat exchanger 22 is located on the upper plate 2a of server rack 2. As in Fig. As shown in Figure 17, the first heat exchanger 22 is designed in the form of a flat plate. The first heat exchanger 22 has an inlet section 25a, to which the refrigerant R is supplied from the outlet-side distributor 15, and an outlet section 25b, which discharges the refrigerant R towards the inlet-side distributor 12. The first heat exchanger 22 is installed such that it is inclined with respect to a horizontal plane HL, so that the inlet section 25a is located above the outlet section 25b.

[0194] The distributor 27 can temporarily store the refrigerant R cooled by the first heat exchanger 22.

[0195] Valve 28 is located in inlet line 121c. Valve 28 opens and closes inlet line 121c. (Control unit)

[0196] The control unit 270 controls the operation of the individual configurations of the cooling system 201. The control unit 270 controls, for example, the opening and closing of the valve 28. (Method for operating the cooling system)

[0197] An example of a method for operating the cooling system 201 according to the present embodiment is described.

[0198] The control unit 270 opens the valve 28 of the inlet line 121c in advance. Accordingly, the natural circulation line 121 is opened, and the refrigerant R can flow through the natural circulation line 121.

[0199] Subsequently, when the heat-generating body 3c is operated, it generates heat, and heat exchange between the refrigerant R and the heat-generating body 3c is initiated in the cooling device 11. Accordingly, the heat-generating body 3c is cooled, and the refrigerant R is heated by the waste heat from the heat-generating body 3c. When the refrigerant R is heated in the cooling device 11, it boils, and its density decreases. This phenomenon occurs in each cooling device 11. Consequently, an upward flow is generated from the cooling unit 10 towards the first heat exchanger 22. Therefore, the refrigerant R, which is subject to heat exchange with the heat-generating body 3c in each cooling device 11, is conveyed to the first heat exchanger 22 via the first natural circulation line 121a.

[0200] Air A is supplied to the first heat exchanger 22 by the blower 23. The first heat exchanger 22 performs the heat exchange between the refrigerant R and the outside air A, transferring the heat from the refrigerant R to the air A. The air A, heated by the waste heat from the refrigerant, is discharged to the outside via the exhaust air flow path 61 in passage 60.

[0201] On the other hand, the refrigerant R is cooled in the first heat exchanger 22, and its density increases. Accordingly, the refrigerant R is distributed from the first heat exchanger 22 to each cooling device 11 via the second natural circulation line 121b and the inlet line 121c.

[0202] In this way, the refrigerant R circulates naturally in the natural circulation section 120, utilizing the waste heat from the heat-generating body 3c. Accordingly, the heat-generating body 3c is always cooled during operation. (Action effect)

[0203] The cooling system 201 of the present embodiment can exert the following effects.

[0204] In the present embodiment, the cooling system 201 further comprises the passage 60, which is arranged above the first heat exchanger 22. The passage 60 extends in the upward-downward direction Dv and has the internal exhaust gas flow path 61, which carries the air A away from bottom to top.

[0205] The air A surrounding the first heat exchanger 22 is heated by the waste heat of the refrigerant R. The high-temperature air A, heated by the first heat exchanger 22, is directed into passage 60. Consequently, the air A in passage 60 has a higher temperature and a lower density than the air A outside passage 60, resulting in a draft effect (chimney effect). The air A flows from below passage 60 to above it. In this way, the air A is easily drawn into the first heat exchanger 22, thus promoting the cooling of the refrigerant R by the first heat exchanger 22. This improves the cooling capacity of the cooling system 201.

[0206] Furthermore, it is possible to reduce the delivery force, e.g., of the blower 23, which supplies air to the first heat exchanger 22, required to deliver the air A to the first heat exchanger. In the case of a low load, where the load on the heat-generating body 3c is low, the amount of heat generated is small, and thus it is also possible to supply the air A to the first heat exchanger 22 in sufficient quantity via the airflow A due to the draft effect of the passage 60. In this case, the blower 23 can be switched off. Since the refrigerant R can be cooled in this way with high energy efficiency, it is possible to further improve the cooling efficiency of the cooling system 201.

[0207] Furthermore, the first heat exchanger 22 is installed such that the inlet section 25a is located above the outlet section 25b.

[0208] Accordingly, the refrigerant R flows easily and evenly through the first heat exchanger 22 from the supply section 25a to the outlet section 25b. Therefore, it is possible to circulate the refrigerant R efficiently in the natural circulation section 120 and thus further improve the cooling efficiency of the cooling system 201. (Hardware configuration)

[0209] The control units 70, 170 and 270 of the above embodiments are mounted on a computer as shown in Fig. 18 shown. Fig. Figure 18 is an example of a schematic block diagram showing a configuration of the computer on which the control units 70, 170, and 270 are mounted according to each embodiment. A computer 1100 comprises a processor 1110, a main memory 1120, a storage unit 1130, and an interface 1140.

[0210] The operation of each of the functional areas of the control units 70, 170, and 27050 is stored in memory 1130 in a program format. Processor 1110 reads the program from memory 1130 and expands the read program into main memory 1120 to execute the processing described above. Furthermore, processor 1110 allocates a memory area in main memory 1120 according to the program.

[0211] The program can be used to implement some of the functions performed by the Computer 1100. For example, the program can perform the functions in combination with another program already stored in memory 1130, or in combination with another program implemented in a different device. Furthermore, in addition to or instead of the configuration described above, the Computer 1100 can include a custom large-scale integrated circuit (LSI), such as a programmable logic device (PLD). Programmable array logic (PAL), generic array logic (GAL), complex programmable logic device (CPLD), and field-programmable gate array (FPGA) are examples of PLDs. In this case, some or all of the functions implemented by the Processor 1110 can be realized by the integrated circuit.

[0212] A magnetic disk, a magneto-optical disk, and a semiconductor memory are exemplary examples of memory 1130. Memory 1130 can be an internal medium directly connected to a bus of computer 1100, or an external medium connected to computer 1100 via interface 1140 or a communication line. When this program is distributed to computer 1100 via the communication line, the receiving computer 1100 can extend the program in main memory 1120 to perform the processing described above. Memory 1130 can also be a non-transferable physical storage medium.

[0213] Furthermore, the program can be used to implement some of the functions mentioned above. Additionally, the program can be a so-called difference file (difference program) that implements the above functions in combination with another program already stored in memory 1130. (Other embodiments)

[0214] As described above, the embodiments of this disclosure are described in detail with reference to the drawings. However, the specific configurations are not limited to the embodiments and include design changes and the like within a scope that does not deviate from the core of this disclosure. Furthermore, it is possible to combine any of the embodiments and any of the examples of modifications described above in a suitable manner.

[0215] In the above embodiment, the heat-generating body 3c, which is the cooling target of the cooling systems 1, 1A, 1B, 101, 101A, 101B and 201, is a chip such as a CPU or a GPU mounted on the server 3, but the present invention is not limited thereto. The heat-generating body 3c can, for example, be an electronic device mounted in a vehicle.

[0216] In the above embodiment, the cooling device 11 is the cold plate 11a, but the present invention is not limited thereto. The cooling device 11 can, for example, be a container that stores an insulating refrigerant R and immerses the heat-generating body 3c in the refrigerant R.

[0217] In the embodiment above, the first heat exchangers 22 and 22B are the air-cooling radiators 25, which carry out the heat exchange between the air A and the refrigerant R, but the present invention is not limited thereto. For example, the first heat exchangers 22 and 22B can be water-cooling plate type heat exchangers, which carry out the heat exchange between the cooling water and the refrigerant R, like the second heat exchanger 36.

[0218] In the embodiment above, the second heat exchanger 36 is a water-cooling plate heat exchanger 36a, but the present invention is not limited thereto. For example, the second heat exchanger 36 can be an air cooler that performs heat exchange with air and the refrigerant R, like the first heat exchangers 22 and 22B.

[0219] The embodiment described above describes the case in which the switching sections 40 and 140 are operated by the control units 70, 170 and 270, but the present invention is not limited to this. The switching sections 40 and 140 can also be operated manually.

[0220] In the embodiment described above, the shapes of the channels 60 and 160 have been described in detail, but these shapes can be modified as needed. For example, the through-entry sections 62 and 162 are formed in a bell-shaped form extending in the upward-downward direction Dv and decreasing in diameter as it rises, but the present invention is not limited to this. The through-entry sections 62 and 162 can also be formed in a tubular shape with a uniform thickness. <Ergänzende Hinweise>

[0221] The cooling systems 1, 1A, 1B, 101, 101A, 101B and 201 described in the individual embodiments are, for example, the following. (1) Cooling systems 1, 1A and 1B according to a first aspect comprise a cooling unit 10 configured to have a plurality of cooling devices 11 cooling a heat-generating body 3c, an inlet-side distributor 12 distributing a refrigerant R to the cooling devices 11, and an outlet-side distributor 15 from which the refrigerant R is discharged from each of the cooling devices 11, natural circulation sections 20, 20A and 20B configured to have natural circulation lines 21 and 21A connecting the outlet-side distributor 15 and the inlet-side distributor 12, and first heat exchangers 22 and 22B installed at the center of the natural circulation lines 21 and 21A and above the cooling unit 10, and a forced circulation section 30 configured to have a forced circulation line 31. which connects the outlet-side distributor 15 and the inlet-side distributor 12,a second heat exchanger 36, which is provided in the middle of the forced circulation line 31 and has a larger capacity than the first heat exchangers 22 and 22B, and a pump 35, which is provided in the forced circulation line 31 to pump the refrigerant R from the outlet-side distributor 15 to the inlet-side distributor 12.

[0222] With the configuration described above, each cooling device 11 performs heat exchange between the heat-generating body 3c and the refrigerant R to cool the heat-generating body 3c. Conversely, the refrigerant R is heated by the heat generated by the heat-generating body 3c. Consequently, the density of the refrigerant R decreases, and the refrigerant R flows upwards. The natural circulation sections 20, 20A, and 20B utilize this flow to circulate the refrigerant R naturally. In the natural circulation sections 20, 20A, and 20B, the refrigerant R, which is undergoing heat exchange with the heat-generating body 3c, is cooled by the first heat exchangers 22 and 22B and returned to the heat-generating body 3c. Additionally, in the forced circulation section 30, the refrigerant R is forcibly circulated by the pumping force of the pump 35.In forced circulation section 30, the refrigerant R pumped by pump 35 undergoes heat exchange through the heat-generating body 3c, is cooled by the second heat exchanger 36, and returned to the heat-generating body 3c. As described above, the refrigerant R is cooled by the first heat exchangers 22 and 22B in the natural circulation sections 20, 20A, and 20B, and the refrigerant R is cooled by the second heat exchanger 36 in the forced circulation sections 30 and 130. Since the capacity of the second heat exchanger 36 is greater than the capacity of the first heat exchangers 22 and 22B, it is possible, even in a case where the cooling capacity in the first heat exchangers 22 and 22B of the natural circulation sections 20, 20A and 20B is insufficient, to cool the refrigerant R sufficiently in the second heat exchanger 36 by using the forced circulation section 30.

[0223] (2) The cooling systems 1, 1A and 1B according to a second aspect are the cooling systems 1, 1A and 1B according to the first aspect, wherein the cooling systems may include a switching section 40 configured to switch a flow system for the refrigerant R to at least one of the natural circulation lines 21 and 21A and the forced circulation line 31.

[0224] Accordingly, if the heat-generating body 3c can be sufficiently cooled by the cooling capacity of the first heat exchangers 22 and 22B, the refrigerant R flow system can be connected only to the natural circulation lines 21 and 21A. Therefore, the refrigerant R, which is subject to heat exchange with the heat-generating body 3c, can be cooled using only the first heat exchangers 22 and 22B. Since only the first heat exchangers 22 and 22B are used, the amount of energy required to operate the cooling systems 1, 1A, and 1B can be reduced. On the other hand, in a case where the cooling capacity of the first heat exchangers 22 and 22B is insufficient for the amount of heat generated, it is possible to switch the refrigerant R flow system only to the forced circulation line 31 or to both the natural circulation lines 21 and 21A as well as to the forced circulation line 31.Since the refrigerant R, which is subject to heat exchange with the heat-generating body 3c, can be cooled by using the second heat exchanger 36 with a larger capacity than the first heat exchangers 22 and 22B, it is possible to cool the refrigerant R sufficiently.

[0225] (3) The cooling systems 1, 1A and 1B according to a third aspect are the cooling systems 1, 1A and 1B according to the first or second aspect, in which the second heat exchanger 36 may be arranged below the cooling unit 10.

[0226] In the forced circulation section 30, the refrigerant R circulates primarily due to the pumping action of the pump 35. Thus, the refrigerant R supplied to the second heat exchanger 36 is directed into the second heat exchanger 36 before it completely evaporates. Accordingly, the density of the refrigerant R supplied to the second heat exchanger 36 is higher than the density of the refrigerant R supplied to the first heat exchangers 22 and 22B. A refrigerant R with a higher density is likely to accumulate at the bottom. Therefore, by arranging the second heat exchanger 36 below the cooling unit 10, as in the present embodiment, the refrigerant R can be supplied to the second heat exchanger 36 more easily.

[0227] (4) The cooling systems 1 and 1B according to a fourth aspect are the cooling systems 1 and 1B according to one of the first to third aspects, wherein the natural circulation line 21 may have an inlet line 21c which is arranged above the plurality of cooling devices 11 in order to introduce the refrigerant R, which is subject to heat exchange in the first heat exchanger 22, into the inlet-side distributor 12, and the pump 35 may be arranged below the plurality of cooling devices 11.

[0228] In the present aspect, the inlet line 21c is arranged above the majority of the cooling units 11. This allows the length of the flow path of the natural circulation section 20 to be shortened. Therefore, it is possible to limit the pressure loss in a case where the refrigerant R is caused to circulate naturally.

[0229] On the other hand, the refrigerant R, whose density increases upon cooling, is supplied to the pump 35. The high-density refrigerant R is likely to sink. Therefore, the refrigerant R can be easily supplied to the pump 35 if the pump 35, as in the present embodiment, is arranged below the plurality of cooling devices 11. Accordingly, it is possible to stably pump the refrigerant R from the pump 35 to each cooling device 11.

[0230] (5) The cooling systems 1, 1A and 1B according to a fifth aspect are the cooling systems 1, 1A and 1B according to any one of the first to fourth aspects, wherein the cooling systems may include a passage 60 configured to be located above the first heat exchangers 22 and 22B and extending in an upward-downward direction Dv, wherein the passage 60 has an internal exhaust air flow path 61 which carries away air A from bottom to top.

[0231] The air A surrounding the first heat exchangers 22 and 22B is heated by the waste heat of the refrigerant R. The high-temperature air A, heated by the first heat exchangers 22 and 22B, is directed into passage 60. Consequently, the air A in passage 60 has a higher temperature and a lower density than the air A outside passage 60, resulting in a draft (chimney effect). The air A flows from below passage 60 to above it. Therefore, the air A can be easily supplied to the first heat exchangers 22 and 22B, thus promoting the cooling of the refrigerant R by the first heat exchangers 22 and 22B. Furthermore, it is possible to reduce the driving force, e.g., of the blower 23, which delivers air to the first heat exchangers 22 and 22B, which is necessary to transport the air A to these heat exchangers.

[0232] (6) The cooling systems 1, 1A and 1B according to a sixth aspect are the cooling systems 1, 1A and 1B according to any one of the first to fifth aspects, wherein the first heat exchangers 22 and 22B may have an inlet section 25a to which the refrigerant R is supplied from the outlet-side distributor 15 and an outlet section 25b which discharges the refrigerant R towards the inlet-side distributor 12, and the first heat exchangers 22 and 22B may be installed such that the inlet section 25a is arranged above the outlet section 25b.

[0233] Accordingly, the refrigerant R flows easily and evenly through the first heat exchangers 22 and 22B from the supply area 25a to the outlet area 25b.

[0234] (7) Cooling systems 101, 101A and 101B according to a seventh aspect comprise a cooling unit 10 configured to have a plurality of cooling devices 11 cooling a heat-generating body 3c, an inlet-side distributor 12 distributing a refrigerant R to the cooling devices 11, and an outlet-side distributor 15 from which the refrigerant R is discharged from each of the cooling devices 11, a natural circulation section 120 configured to have a natural circulation line 121 connecting the outlet-side distributor 15 and the inlet-side distributor 12, and a first heat exchanger 22 installed at the midpoint of the natural circulation lines 21, 21A and 121 and above the cooling unit 10, and a forced circulation section 130 configured to have a forced circulation line 131,which connects a downstream side of the first heat exchanger 22 in the natural circulation line 121 and the inlet-side distributor 12, and has a pump 35 which is provided in the forced circulation line 131 to pump the refrigerant R from the outlet-side distributor 15 to the inlet-side distributor 12, wherein the natural circulation line 121 has an inlet line 121c which is arranged above the plurality of cooling devices 11 in order to introduce the refrigerant R, which is subject to heat exchange in the first heat exchanger 22, into the inlet-side distributor 12, and the pump 35 is arranged below the plurality of cooling devices 11.

[0235] (8) The cooling systems 101, 101A and 101B according to an eighth aspect are the cooling systems 101, 101A and 101B according to the seventh aspect, wherein the cooling systems may include channels 60 and 160 configured to be located above the first heat exchanger 22 and extending in an upward-downward direction Dv, wherein the channels 60 and 160 have internal exhaust air flow paths 61 and 161 that carry air A from bottom to top.

[0236] (9) The cooling system 101B according to a ninth aspect is the cooling system 101B according to the eighth aspect, wherein the cooling system may comprise a plurality of cooling units 10 and a plurality of natural circulation sections 120 and a plurality of forced circulation sections 130 for each of the cooling units 10, wherein the passage 160 may have a passage inlet section 162 arranged above each of the plurality of first heat exchangers 22 to introduce air A into the passage 160 from below, a passage head section 163 connecting the upper end sections of the multiple passage inlet sections 162 to cause the air A introduced by each of the passage inlet sections 162 to be combined, and a passage outlet section 164 extending upward from the passage head section 163 to discharge the air A combined by the passage head section 163 upward.

[0237] With the above configuration, it is possible to combine the air A heated by the multiple first heat exchangers 22 into a single flow. Accordingly, it is possible to accelerate the flow of air A from below passage 160 to above passage 160. Furthermore, it is possible to achieve space savings.

[0238] (10) A cooling system 201 according to a tenth aspect comprises a cooling unit 10 configured to have a plurality of cooling devices 11 cooling a heat-generating body 3c, an inlet-side distributor 12 distributing a refrigerant R to the cooling devices 11, and an outlet-side distributor 15 from which the refrigerant R is discharged from each of the cooling devices 11, a natural circulation section 120 configured to have a natural circulation line 121 connecting the outlet-side distributor 15 and the inlet-side distributor 12, a first heat exchanger 22 installed at the center of the natural circulation line 121 and above the cooling unit 10, and a passage 60 configured to be located above the first heat exchanger 22 and extending in an upward-downward direction Dv, the passage forming an internal exhaust gas flow path 61which carries air A from bottom to top.

[0239] (11) The cooling system 201 according to an eleventh aspect is the cooling system 201 according to the tenth aspect, wherein the first heat exchangers 22 and 22B may have an inlet section 25a, to which the refrigerant R is supplied from the outlet-side distributor 15, and an outlet section 25b, which discharges the refrigerant R towards the inlet-side distributor 12, and the first heat exchanger 22 may be installed such that the inlet section 25a is arranged above the outlet section 25b. INDUSTRIAL APPLICABILITY

[0240] According to the cooling system of the present disclosure, it is possible to improve the cooling efficiency. REFERENCE MARK LIST 1 Cooling system 2 server racks 2a upper plate 3 servers 3a Housing 3b Server board 3c Heat-generating body 4 probes 6 Flow system 10 cooling units 11 Cooling unit 11a Cold plate 12 Inlet-side distributor 13 Inlet-side branch line 14 valve 15 Outlet-side distributor 16 Outlet-side branch line 20 natural circulation route 21 Natural circulation conduit 21a First natural circulation line 21b Second natural circulation line 21c Entrance line 22 First heat exchanger 23 blowers 24 Relief valve 25 radiators 25a Supply area 25b Outlet area 30 Forced Circulation Section 31 Forced circulation line 31a First forced circulation line 31b Second forced circulation line 31c Third forced circulation line 32 Separate CDU 33 Cooling unit 34 containers 35 pump 36 Second heat exchanger 36a Water cooling plate 36b valve 37 Pump line 38 Merger Management 40 switching distance 41 First switching valve 42 Second switching valve 43 Third switching valve 44 Fourth switching valve 45 Fifth switching valve 46 Sixth switching valve 50 passes 51 Supply Management 52 Storage valve 60 passes 61 Exhaust gas flow path 61a Inlet opening section 61b Outlet opening section 62 Transition introduction section 63 Main passage body 64 Through outlet section 70 Control unit 71 Recording section 72 Heat generation temperature determination section 73 Control section 73a Switching control section 73b Pump control section A air Dv Up-Down Direction Dvu top DVD bottom side HL Horizontal Plane R Refrigerant W cooling water 1A cooling system 20A Natural Circulation Route 21A Natural Circulation Line 21Ac inlet line 1B Cooling system 20B Natural Circulation Route 22B First heat exchanger 26 Connecting section 101 Cooling system 120 natural circulation route 121 Natural circulation line 121a First natural circulation line 121b Second natural circulation conduit 121c Admission line 27 distributors 130 Forced Circulation Section 131 Forced circulation line 140 switching distance 141 First switching valve 142 Second switching valve 170 control unit 171 Recording section 172 Heat generation temperature determination section 173 Tax Section 173a Switching control section 173b Pump control section 101A Cooling System 101B Cooling System 5 Device part 106 Flow system 160 passes 161 Exhaust gas flow path 161a Inlet opening section 161b Outlet opening section 162 Transition introduction section 163 Through head section 164 Through-outlet area 201 Cooling system 28 valve 270 control unit 1100 computers 1110 processor 1120 main memory 1130 storage 1140 interface QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] JP 2023-086837

[0002]

Claims

[1] A cooling system comprising a cooling unit configured to have a plurality of cooling devices that cool a heat-generating body, an inlet-side distributor that distributes a refrigerant to the cooling devices, and an outlet-side distributor from which the refrigerant is discharged from each of the cooling devices; a natural circulation section configured to include a natural circulation line connecting the outlet-side manifold and the inlet-side manifold, and a first heat exchanger installed in the middle of the natural circulation line and above the cooling unit; and a forced circulation section configured to include a forced circulation line connecting the outlet-side manifold and the inlet-side manifold, a second heat exchanger provided in the middle of the forced circulation line and having a larger capacity than the first heat exchanger, and a pump provided in the forced circulation line to pump the refrigerant from the outlet-side manifold to the inlet-side manifold. [2] The cooling system according to claim 1, further comprising: a switching section configured to switch a refrigerant flow system to the natural circulation line and / or the forced circulation line. [3] The cooling system according to claim 1 or 2, wherein the second heat exchanger is arranged below the cooling unit. [4] Cooling system according to claim 1 or 2, wherein the natural circulation line has an inlet line arranged above the majority of cooling devices for introducing the refrigerant, which is subject to heat exchange in the first heat exchanger, into the inlet-side distributor, and the pump is located below the majority of cooling devices. [5] The cooling system according to claim 1 or 2, further comprising: a passage configured to be located above the first heat exchanger and extending in an upward-downward direction, the passage having an internal exhaust gas flow path that carries air from bottom to top. [6] The cooling system according to claim 1 or 2, the first heat exchanger has a feed section to which the refrigerant is fed from the outlet-side distributor, and an outlet section that discharges the refrigerant towards the inlet-side distributor, and the first heat exchanger is installed such that the feed section is located above the outlet section. [7] A cooling system comprising a cooling unit configured to have a plurality of cooling devices that cool a heat-generating body, an inlet-side distributor that distributes a refrigerant to the cooling devices, and an outlet-side distributor from which the refrigerant is discharged from each of the cooling devices; a natural circulation section configured to include a natural circulation line connecting the outlet-side manifold and the inlet-side manifold, and a first heat exchanger installed in the middle of the natural circulation line and above the cooling unit; and a forced circulation section configured to include a forced circulation line connecting a downstream side of the first heat exchanger in the natural circulation line and the inlet-side manifold, and a pump provided in the forced circulation line to pump the refrigerant from the outlet-side manifold to the inlet-side manifold, wherein the natural circulation line has an inlet line located above the majority of cooling devices to introduce the refrigerant, which is subject to heat exchange in the first heat exchanger, into the inlet-side distributor, and the pump is located below the majority of cooling devices. [8] The cooling system according to claim 7, further comprising: a passage configured to be located above the first heat exchanger and extending in an upward-downward direction, the passage having an internal exhaust gas flow path that carries air from bottom to top. [9] The cooling system according to claim 8, further comprising: a variety of cooling units; and a variety of sections with natural circulation and a variety of sections with forced circulation, provided for each of the cooling units, the passage exhibits the following a through-flow inlet section arranged above each of the several first heat exchangers to introduce air into the through-flow from below, a through-head section that connects the upper end sections of the multiple through-inlet sections to cause the air introduced by each of the through-inlet sections to be combined, and a through-outlet section extending upwards from the through-head section to expel the air mixed by the through-head section upwards. [10] A cooling system comprising a cooling unit configured to have a plurality of cooling devices that cool a heat-generating body, an inlet-side distributor that distributes a coolant to the cooling devices, and an outlet-side distributor from which the coolant is discharged from each of the cooling devices; a natural circulation section configured to include a natural circulation line connecting the outlet-side manifold and the inlet-side manifold, and a first heat exchanger installed in the middle of the natural circulation line and above the cooling unit; and a passage configured to be located above the first heat exchanger and extending in an upward-downward direction, the passage having an internal exhaust gas flow path that expels air from bottom to top. [11] The cooling system according to claim 10, the first heat exchanger has a feed section to which the refrigerant is fed from the outlet-side distributor, and an outlet section that discharges the refrigerant towards the inlet-side distributor, and the first heat exchanger is installed such that the feed section is located above the outlet section.

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