JP5860728B2 - Electronic equipment cooling system - Google Patents

Description

  The present invention relates to a cooling system for electronic equipment. For example, in a server or the like in which a plurality of server units installed in a data center or the like are detachably stacked, the heat of heating elements such as a plurality of CPUs mounted on a motherboard in each server unit is passed through the server installation space. The present invention relates to a cooling system for electronic devices that can be discharged directly to the outside.

As background art in this technical field, there is JP-A-9-139453 (Patent Document 1).
Patent Document 1 discloses that an evaporator in which a refrigerant liquid is sealed and at least one semiconductor element is pressure-welded to an outer surface thereof, a refrigerant vapor generated from the evaporator is condensed, and the condensed refrigerant liquid is evaporated. In a semiconductor cooling device provided with a condenser that circulates to the heat generating surface, the semiconductor element is brought into close contact with the heat transfer surface in the evaporator, and one or more metallic nets are stacked and formed on the heat transfer surface. An object of the present invention is to provide a semiconductor cooling device that prevents a rapid temperature rise of an element such as a CPU due to drying and improves cooling efficiency. Further, the lower or upper side of the heat transfer surface in the evaporator to which the semiconductor element is pressure bonded is made higher than the inner wall surface of the evaporator so that the heat transfer surface is inclined. . Further, the height of the heat transfer surface in the evaporator to which the semiconductor is pressure-welded is increased as the heat transfer surface located below. Moreover, the content characterized by having provided the guide in the heat-transfer surface lower part so that the vapor bubble generated from the heat-transfer surface of the lower position may not pass on the heat-transfer surface of an upper position is described.

  Moreover, there exists Unexamined-Japanese-Patent No. 2010-79403 (patent document 2). In Patent Document 2, a cooling system for an electronic device such as a blade server in which a plurality of blades are detachably mounted in a housing and semiconductor devices including a plurality of CPUs having different calorific values are mounted therein, A thermosiphon that transports heat from a device with a relatively large calorific value to the outside, a thermal highway that transports heat from a device with a relatively small calorific value to the thermosyphon, and the insertion of a blade into the device housing Accordingly, the contents including a thermal connector for thermally connecting the thermosiphon and the thermal highway are described.

JP-A-9-139453 JP 2010-79403 A

  As a cooling system for electronic devices, for example, a condenser that cools the vapor of refrigerant in a first evaporative cooling device (thermosyphon) that cools heating elements such as a plurality of CPUs in a plurality of server units installed in a server rack The steam / refrigerant pipe connected to the evaporator of the second vaporization type cooling device (thermal highway) that is thermally coupled to the outside through the thermal connector is cooled by an outdoor water cooler that is the third water cooling type cooling device. By connecting to a top box provided at the top of the server rack that contains a condenser (heat exchanger) that condenses by exchanging heat with water, heat from the heat generating elements such as CPU in the server unit is not passed through the server installation space. When technology for a cooling system for electronic devices such as servers that can be directly discharged to the outdoors is assumed, the thermal evaporation of the second evaporative cooling device (thermal highway) Evaporator liquid generated by improving the heat transfer performance of the evaporator built in the reactor in the allowable installation space and by condensing refrigerant in the piping of the steam / liquid and heat exchanger during operation The subject which prevents the rapid temperature rise by drying of the heat-transfer surface by the fall of a surface is assumed.

  One object of the present invention is to provide an electronic device cooling system having a suitable thermal connector as an electronic device cooling system.

  In order to solve the above problems, for example, the configuration described in the claims is adopted.

The present application includes a plurality of means for solving the above-described problems. For example, the first application is provided in the heat-dissipating part of the heat-generating element such as the CPU of the motherboard arranged in the tray of the server unit installed in the server rack. An evaporator, a thermal connector detachably connected to the heat radiating portion, and a first condenser fixed to be connectable to the thermal connector including a second evaporator outside the tray in the tray. A first evaporative cooling device comprising a vapor / refrigerant pipe connecting the first evaporator and the first condenser, a second condenser cooled by cold water flowing from the outside, and the thermal A second evaporator having a second vaporization type cooling device comprising a vapor / refrigerant pipe connecting the second evaporator in the connector and the second condenser; A heat transfer plate whose surface forms the heat transfer surface of the thermal connector and whose opposite surface forms the evaporation surface in the second evaporator is disposed vertically in the second evaporator, and the heat transfer A vertical slit for sucking up the refrigerant by surface tension is provided on the surface on the evaporation surface side of the plate, and a liquid supply guide for supplying the refrigerant is disposed between the liquid surface of the refrigerant and the height direction of the evaporation surface. They are provided in parallel.

  ADVANTAGE OF THE INVENTION According to this invention, the cooling system of the electronic device which has a suitable thermal connector as a cooling system of an electronic device can be provided.

  More specifically, for example, according to the present invention, the heat transfer performance of the evaporator of the thermal connector can be improved in the allowable installation space as a cooling system for electronic equipment. In addition, rapid temperature rise due to drying of the heat transfer surface due to a decrease in the liquid level of the evaporator caused by the residence of condensed refrigerant in the piping of the steam / liquid and heat exchanger piping during operation can be prevented. it can.

The perspective view which shows the whole structure of the server cooling system of embodiment of this invention. The perspective view of the server unit which attaches the 1st cooling device (thermo siphon) to the motherboard of embodiment of this invention. The perspective view which shows the 2nd cooling device (thermal highway) of embodiment of this invention. The longitudinal cross-sectional view of the heat exchanger which is the condenser of the thermal highway of embodiment of this invention. The top view which shows the thermal connector of the thermal highway of embodiment of this invention. The thermal connector longitudinal cross-sectional view of the thermal highway of embodiment of this invention. The perspective view of the metal-mesh provided in the refrigerant | coolant supply guide of the thermal connector of embodiment of this invention, and its upper surface. The longitudinal cross-sectional view of the thermal connector which shows the motion of the refrigerant | coolant inside the evaporator of the thermal connector at the time of CPU operation | movement of embodiment of this invention. The longitudinal cross-sectional view of the thermal connector which shows the motion of the other refrigerant | coolant inside the evaporator of a thermal connector at the time of CPU operation | movement of embodiment of this invention. The longitudinal cross-sectional view of the thermal connector which uses a porous boiling heat transfer surface as a high performance heat transfer surface for the heat transfer surface in the evaporator of the thermal connector of embodiment of this invention.

  Hereinafter, embodiments will be described with reference to the drawings. In addition, since the structure which attached | subjected the same code | symbol shown in each figure has the same function, those description may be abbreviate | omitted.

  The overall configuration of the server cooling system of the present invention will be described with reference to FIG. In each rack of the server rack 100, server units 101 on which motherboards 102 are mounted are stacked in two rows on the left and right. However, FIG. 1 is omitted and only a one-stage server unit is shown. The server unit 101 is provided with a first evaporative cooling device (hereinafter sometimes referred to as a thermosiphon) 104 that cools heating elements such as CPUs to the left and right motherboards, respectively, and a second evaporative cooling device ( Hereinafter, it may be referred to as a thermal highway.) The heat of a heating element such as a CPU is discharged through 105 and the thermal connector 106. The heat transmitted to the thermal highway 105 is supplied by a third water-cooling type cooling device 108 that is installed outdoors and is provided with an outdoor water cooler 109 by a heat exchanger 134 that is housed in a top box 107 provided at the top of the server rack 100. Cooled with cold water.

  The thermosiphon 104 attached to the motherboard 102 will be described in detail with reference to FIG. In FIG. 2, two (plural) motherboards 102 are mounted on one tray 137. A plurality of CPUs (103) are attached to the mother board 102, and a thermosiphon evaporator 110 is attached to a heat radiation portion of the CPU (103) which is a heat generating element. Each thermosiphon evaporator 110 is connected to each other by a thermosiphon vapor / liquid pipe 135 through which the vapor and condensed return refrigerant are passed, and further condensed with vapor from one of the thermosiphon evaporators 110 connected. A thermosiphon condenser 111 is connected via a thermosiphon vapor / liquid pipe (2) 136 (where “(2)” means “second”) through which the return refrigerant passes. Further, the thermosiphon condenser 111 is provided with a thermal connector 106 (details will be described later) and a thermal connector 106 of a second evaporative cooling device (thermal highway) in a notch 138 provided in the tray side plate 139 of the tray 137 on which the motherboard 102 is mounted. It is attached so that the surfaces can be joined together. The thermosiphon condenser 111 is attached to the left and right motherboards 102 on both sides of the tray 137, respectively.

  Next, the configuration of the second vaporization type cooling device (thermal highway) 105 will be described with reference to FIG. The second evaporative cooling device (thermal highway) 105 incorporates an evaporator 112 that evacuates and encloses the refrigerant, a thermal connector 106 having a heat transfer surface on the back surface of the evaporator 112, and a top box 107 shown in FIG. A heat exchanger 134 that forms a condenser provided inside, a steam / liquid pipe 140 and a steam / liquid pipe (through which the steam of the thermal highway connecting the thermal connector 106 and the heat exchanger 134 and the condensed return refrigerant are passed ( 2) 141.

  Steam / liquid piping 140 and steam / liquid piping (2) 141 are connected via elbow piping. As will be described below, the liquid pipe of the steam / liquid pipe 140 is inclined with respect to the horizontal plane so that the condensate can be easily returned. Therefore, a different number is attached to the vertical pipe of the steam / liquid pipe (2) 141. . The thermal highway connecting the steam / liquid pipe 140, the steam / liquid pipe (2) 141, and the heat exchanger 134 is joined to the left and right thermosiphon condensers 111, respectively, to the left and right of each rack of the server rack 100. One set is arranged. The plurality of heat exchangers 134 are arranged in parallel in the same space in the top box.

  Referring to FIG. 4, the flow of the refrigerant in the thermal highway 105 will be described. The refrigerant evaporated in the evaporator 112 shown in FIG. 3 in the thermal connector 106 is arranged vertically through the vapor / liquid pipe 140 shown in FIG. The steam / liquid pipe (2) 141 flows into the heat exchanger 134. Here, in the cooling water flow path 145 outside the heat exchanger 134 forming a double circular tube, cold water supplied from the outdoor water cooler 109 shown in FIG. By flowing out from the outlet 147, the vapor of the refrigerant flowing into the heat exchanger 134 is cooled from the tube wall to become a liquid refrigerant. The liquid refrigerant returns inside the heat exchanger 134 along the lower pipe wall, falls in the vertically disposed steam / liquid pipe (2) 141 due to a drop, and flows again in the steam / liquid pipe 140. It is recovered into the evaporator 112 in the thermal connector 106.

  Accordingly, the refrigerant level in the evaporator 112 in the thermal connector 106 stays in the vapor / liquid pipe 140 and the heat exchanger 134 in the middle when the CPU operates and generates heat in the encapsulated stationary state. As a result, the liquid level of the refrigerant decreases. If the amount of decrease is large, the entire heat transfer surface may dry out, and the CPU may rapidly increase in temperature. Therefore, in order to reduce the amount of refrigerant staying in the pipe as much as possible, the horizontally arranged heat exchanger 134 and the steam / liquid pipe 140 are inclined in such a direction that the refrigerant inside easily returns to the evaporator 112. . By this, the liquid level fall of the evaporator 112 in a thermal connector can be relieved. That is, the horizontal vapor / refrigerant pipe connected to the thermal connector of the second vaporization type cooling device (thermal highway) 105 and the condenser (heat exchanger 134) in the top box 107 are inclined with respect to the horizontal plane. It is desirable.

  The thermal connector 106 and the thermosiphon condenser 111 can be provided with a hole in one outer periphery, machine a female screw on the other outer periphery, and connect each member with a screw. In addition, the thermal connector 106 and the thermosiphon condenser 111 usually use copper-based metal to improve heat transfer. If the strength of the screw portion is insufficient, the outer periphery of the thermal connector 106 and the thermosiphon condenser 111 Drill holes in each of them, and one is provided with holes on the outer periphery, and the other is sandwiched from both sides with a strong metal plate such as a stainless steel plate with screw holes on the outer periphery, and they are joined together with screws. It is also possible. However, this structure is not shown in the figure.

  FIG. 5 is a plan view showing a thermal connector of the thermal highway according to the embodiment of the present invention, and has a heat transfer plate 115 on at least one surface of the thermal connector 106.

  Next, the internal structure of the thermal connector 106 will be described with reference to FIG. The heat transfer plate of the thermal connector 106 is arranged vertically, and a refrigerant reservoir 149 is provided at a lower half height (refrigerant liquid level 156 is indicated by a dotted line). In addition, a slit 151 is provided on the heat transfer surface of the heat transfer plate, and the refrigerant in the liquid reservoir is supplied to the heat transfer surface by surface tension. In addition, the height of the refrigerant | coolant which raises by surface tension with respect to the slit width provided in a heat-transfer surface is generally in inverse proportion to a slit width, when the same substance is used for a refrigerant | coolant. Therefore, the smaller the slit width is, the higher the refrigerant is on the heat transfer surface, and the smaller the pitch of each slit is, the more the heat transfer surface can be supplied in the form of a thin film with the refrigerant. However, as the slit width and pitch are reduced, the processing becomes more difficult and the processing cost increases, so there is an appropriate size.

  Further, a liquid supply guide 132 for further supplying a refrigerant is provided at an intermediate position in the height direction of the heat transfer surface. Further, as shown by the steam flow 153, the discharge of the steam in the evaporator 112 and the return refrigerant condensed in the heat exchanger 134 are shown on the liquid supply guide 132 by the liquid flow 154 indicated by the solid line arrow. The steam / liquid pipe opening 144, which is the opening of the steam / liquid pipe 140 of the thermal highway, is disposed on the liquid supply guide 132. Further, a steam passage 152 is provided on the end side of the liquid supply guide 132 so that the steam can be discharged from the lower portion of the evaporator 112, and a weir is provided in a portion where the wall surface on the liquid supply guide 132 is not restricted. Side plate 150 is provided. The height of the side plate 150 is set from the height of the refrigerant stored on the liquid supply guide 132. When the refrigerant condensing more than that height returns, it falls from the top of the side plate provided in the liquid supply guide to the lower refrigerant liquid reservoir, so that the refrigerant does not disappear from the lower refrigerant liquid reservoir. The liquid supply guide 132 is preferably provided in parallel with the liquid level 156 between the liquid level 156 and the height direction of the evaporation surface.

  Next, an example in which a metal mesh 133 is provided so as to uniformly distribute the refrigerant condensed and recovered over the entire upper surface of the liquid supply guide 132 will be described with reference to FIG. FIG. 7 shows an example of a copper wire or a stainless steel wire mesh overlapped at equal pitches.

  Further, when the amount of heat generated by the CPU increases, the amount of the return refrigerant condensed in the piping in the middle of the thermal highway increases as the refrigerant evaporates, and the liquid level 156 of the refrigerant decreases significantly. Therefore, a liquid storage buffer 142 is provided to increase the amount of refrigerant enclosed in the evaporator of the thermal connector 106. Further, a partition plate 148 that connects the space in the liquid storage buffer 142 and the space of the evaporator 112 and shields half of the cross section of the connection portion is provided. By providing a liquid storage buffer 142 in which the internal space communicates next to the evaporator 112 built in the thermal connector 106, the amount of refrigerant enclosed in the evaporator can be increased by a factor of two compared to the case of the evaporator alone.

  When the operating state of the CPU is the maximum, if only the evaporator 112 is used, the liquid level of the refrigerant in the evaporator is lowered and the heat transfer surface may be dried. However, as a result of providing the liquid storage buffer 142, the refrigerant Even if the liquid level of the liquid drops, the entire heat transfer surface does not dry and is within the allowable range.

  Further, the heat transfer coefficient of the heat transfer surface is balanced by the refrigerant rising by the slit and evaporating on the heat transfer surface when the heat generation of the CPU is small.

As shown in FIG. 8, when the CPU has a medium calorific value with respect to the rated load, boiling occurs due to heat generation on the heat transfer surface in the lower refrigerant reservoir 149 in the evaporation chamber. As shown, the liquid level of the refrigerant fluctuates, and the fluctuation propagates to the refrigerant liquid level of the adjacent liquid reservoir buffer 142.
As a result, the fluctuation waveform of the liquid level collides with the wall in the traveling direction of the liquid storage buffer 142 and reverses, and the flow path cross section is reduced by the partition plate 148, so that the refrigerant on the opening side returns to the return liquid indicated by the solid line arrow. As shown by the flow 157, the vehicle passes over the side plate 150 and flows onto the liquid supply guide 132 so that the refrigerant can be periodically supplied onto the liquid supply guide. That is, it is desirable to provide a partition plate 148 that partially shields the cross section of the communication portion at the communication position between the evaporator 112 and the liquid storage buffer 142.

  Further, when the heat generation amount of the CPU reaches the maximum rated load, as shown in FIG. 9, the refrigerant in the liquid reservoir 149 at the lower part of the evaporator expands explosively due to boiling by heating from the heat transfer surface. Arise. At this time, as indicated by the upper liquid flow 159 and the lateral liquid flow 160, the refrigerant expanded from the vapor passage 152 provided in the liquid supply guide 132 flows directly into the upper part of the liquid supply guide 132, and heat transfer on the liquid supply guide 132 is performed. Splashes on the surface. As a result, the refrigerant can be periodically supplied not only to the slit of the heat transfer surface under the liquid supply guide 132 but also to the slit of the heat transfer surface on the liquid supply guide 132, and evaporation due to boiling is performed. Efficient heat exchange is possible without drying.

  6, 8, 9, and 10, three protruding portions on the upper surface and the lower surface of the thermal connector 106 are portions having screw holes for assembling the thermal connector. It can be omitted when assembling by other methods without using screws.

  FIG. 10 shows an example in which a high performance heat transfer surface 155 (for example, a porous boiling heat transfer surface) is provided on the surface of the heat transfer plate as an example of the internal structure of the thermal connector 106. The high performance heat transfer surface 155 is formed with a porous heat transfer surface. The high-performance heat transfer surface 155 continuously forms boiling by forming a refrigerant film on the surface, and obtains high-performance heat transfer performance. Therefore, similarly, the lower part of the high-performance heat transfer surface 155 is evaporated by directly immersing the refrigerant in the liquid reservoir 149, and the upper part of the high-performance heat transfer surface 155 is dripped as uniformly as possible in the longitudinal direction from the upper part. Structure. Therefore, in this case, it is desirable to provide the surface of the liquid supply guide 132 as high as possible in the height direction of the high performance heat transfer surface 155. That is, in the first embodiment, the refrigerant supply guide 132 for supplying the refrigerant to the intermediate position in the height direction of the heat transfer surface is provided, but in the second embodiment, the position is higher than the intermediate position in the height direction of the heat transfer surface. It is desirable to provide a liquid supply guide 132 on the surface. In addition, a gap flows between the high-performance heat transfer surface 155 and the liquid supply guide 132 so that the refrigerant flows from the liquid supply guide 132 to the high-performance heat transfer surface 155 and the refrigerant can drop on the high-performance heat transfer surface 155. Provided (omitted in FIG. 10).

  Hereinafter, the features of the present invention will be exemplified. For example, in a cooling system for an electronic device, at least a thermal connector that is detachably connected to a heat radiating portion from the electronic device and is capable of transferring heat, and an evaporator in the thermal connector. A condenser connected to the thermal connector, wherein at least one surface of the thermal connector forms a heat transfer surface of the thermal connector connected to the heat radiating portion, and the other surface is inside the thermal connector. An evaporation surface in the evaporator is formed, and the evaporation surface is a heat transfer plate arranged vertically in the evaporator, and a slit that sucks the refrigerant by surface tension on the surface on the evaporation surface side of the heat transfer plate And a liquid supply guide for supplying the refrigerant is provided between the liquid level of the refrigerant and the height direction of the evaporation surface.

  Further, for example, in the evaporator of the second vaporization type cooling device (thermal highway), a vertical slit is formed on the evaporation side surface of the heat transfer plate arranged vertically. In the evaporator, a liquid supply guide is provided in parallel with the liquid level of the refrigerant between the heat transfer plate height directions, and the vapor / liquid that forms the flow path of the vapor generated in the evaporator and the refrigerant condensed in the condenser. An opening of the pipe is arranged on the upper part of the liquid supply guide. Further, a metal mesh is provided on the upper surface of the liquid supply guide. Further, a steam passage is provided in the liquid supply guide. Further, a side plate having a height capable of storing the refrigerant is provided at an unconstrained end portion of the liquid supply guide.

  Further, for example, a liquid storage buffer whose internal space communicates is provided next to the evaporator built in the connector. In addition, a partition plate that half shields the cross section is provided at a communication position between the evaporator and the liquid storage buffer.

  Also, for example, a server rack cooling system characterized in that a highly efficient porous boiling heat transfer surface is provided on the evaporation surface of the heat transfer plate of the evaporator built in the connector.

  In addition, a lower slit sealed in the evaporator is formed by forming a vertical slit on the evaporation side surface of the heat transfer plate arranged perpendicular to the evaporator built in the connector of the second evaporative cooling device (thermal highway). The liquid in the liquid reservoir is continuously sucked upward by the surface tension, and the thin film is formed to evaporate the refrigerant continuously and efficiently, thereby stabilizing the heat transfer performance.

In the evaporator, a liquid supply guide is provided in parallel to the liquid level of the refrigerant between the height directions of the heat transfer plate, and vapor forming a recovery flow path for the vapor generated in the evaporator and the refrigerant condensed in the condenser -By arranging the opening of the refrigerant pipe above the refrigerant supply guide, the condensed refrigerant flows into the liquid supply guide, so that the lower half of the heat transfer plate sucks up the refrigerant from the liquid reservoir in the evaporator. At the same time, the upper half of the heat transfer plate is condensed and sucked in and flows in from the liquid supply guide surface.
In addition, by providing a metal mesh on the upper surface of the liquid supply guide, the refrigerant that is condensed and flows in is uniformly held on the liquid supply guide until it evaporates, so that evaporation from the heat transfer plate is maintained. The Further, since a vapor passage is provided in the liquid supply guide, the refrigerant gas that evaporates in the evaporation chamber below the liquid supply guide also flows on the liquid supply guide through the vapor passage. Therefore, the steam pipe disposed on the liquid supply guide It becomes easy to flow from the to the condenser in the top box, and the circulation of the refrigerant can be promoted.
In addition, by providing a liquid storage buffer that communicates with the internal space next to the evaporator built in the connector, when the server operates and the refrigerant begins to circulate in the pipe, it stays in the pipe constituting the thermal highway. Although the liquid level of the refrigerant in the evaporator is lowered by the volume, it is possible to reduce this liquid level drop. Also, a partition plate that partially shields the cross section that communicates with the communication position between the evaporator and the liquid storage buffer is provided, and a side plate that is high enough to store liquid at the unrestricted end of the refrigerant supply guide. Is provided. As a result, when the load on the server increases, a sudden boiling occurs on the heat transfer surface below the refrigerant supply guide immersed in the heat transfer surface, and the liquid level of the refrigerant under the liquid supply guide fluctuates and waves. start. At this time, the liquid level fluctuation of the liquid reservoir at the bottom of the evaporator propagates to the adjacent liquid reservoir, and when reflected back from the wall surface of the liquid reservoir, the liquid level fluctuation is amplified and returns to the top of the liquid supply guide plate. Come.

  As a result, the refrigerant in the liquid reservoir below the evaporation chamber is periodically supplied onto the liquid supply guide. From the surface of the liquid supply guide, it is sucked up by the surface tension by the slit from above the heat transfer plate. As a result, the refrigerant is sucked up by the surface tension from the lower part and the vicinity where the liquid supply guide is provided on the heat transfer surface, and the refrigerant is constantly supplied to the entire heat transfer surface in the form of a thin film so that efficient evaporation is performed. . Further, when the load on the server increases and near the maximum near the heat transfer surface immersed in the refrigerant reservoir below the heat transfer surface, further explosive boiling occurs, the refrigerant in the liquid reservoir is blown away by the rapidly expanding steam. At that time, a part of the liquid supply guide blows out from the vapor passage provided in the liquid supply guide onto the liquid supply guide, and the refrigerant accumulates on the liquid supply guide by the height of the side plate provided in the liquid supply guide. At the same time, since it is applied to the slit of the heat transfer surface, a thin liquid film is formed on the heat transfer surface, and efficient evaporation is continued.

  Further, by providing a metal plate (for example, a porous boiling heat transfer surface) having a highly efficient heat transfer fin shape on the evaporation surface of the heat transfer plate of the evaporator built in the thermal connector, the inside of the evaporator can be efficiently obtained. The refrigerant can be evaporated.

  In addition, the steam pipe and the condensed refrigerant recovery pipe are inclined with respect to the horizontal plane, so that the vapor from the evaporator rises to the top box and the refrigerant condensed in the condenser (heat exchanger) in the top box. Recovery is smooth. Further, since the refrigerant that has evaporated and condensed in the condenser in the top box in the operation of the server is less likely to stay in the condenser or in the horizontal piping for recovery to the evaporator, the liquid in the evaporator is reduced. Surface degradation is also reduced, and drying of the heat transfer surface can be prevented.

In addition, this invention is not limited to an above-described Example, Various modifications are included.
For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

100 server rack 101 server unit 102 motherboard 103 CPU
104 First evaporative cooling device (thermo siphon)
105 Second evaporative cooling device (thermal highway)
106 Thermal Connector 107 Top Box 108 Third Water Cooling Cooling Device 109 Outdoor Water Cooler 110 Thermosiphon Evaporator 111 Thermosiphon Condenser 112 Evaporator 115 Heat Transfer Plate 132 Liquid Supply Guide 133 Wire Mesh 134 Heat Exchanger 135 Thermosiphon Steam / Liquid Piping 136 Thermosiphon steam / liquid piping (2)
137 Tray 138 Notch 139 Tray side plate 140 Steam / liquid piping 141 Steam / liquid piping (2)
142 Liquid reservoir buffer 143 Heat transfer plate with slit 144 Steam / liquid piping opening 145 Cooling water flow path 146 Cooling water inlet 147 Cooling water outlet 148 Partition plate 149 Liquid reservoir 150 Side plate 151 Slit 152 Steam passage 153 Steam flow 154 Liquid flow 155 High Performance Heat Transfer Surface 156 Liquid Level 157 Return Liquid Flow 158 Fluctuating Liquid Level 159 Upper Liquid Flow 160 Lateral Liquid Flow

Claims (8)

A first evaporator provided in a heat radiating portion of a heat generating element such as a CPU of a motherboard arranged in a tray of a server unit installed in a server rack;
A thermal connector that is detachably connected to the heat radiating portion and capable of transferring heat;
A first condenser fixed to the tray so as to be connectable to the thermal connector containing a second evaporator outside the tray;
A first evaporative cooling device comprising a vapor / refrigerant pipe each connecting the first evaporator and the first condenser;
A second condenser cooled by cold water flowing from the outside;
A second evaporative cooling device comprising a vapor / refrigerant pipe connecting the second evaporator and the second condenser in the thermal connector;
In the second evaporator built in the thermal connector, the first plate forms a heat transfer surface of the thermal connector, and the opposite surface forms a heat transfer plate in the second evaporator. A vertical slit is arranged in the two evaporators, and a vertical slit for sucking up the refrigerant by surface tension is provided on the surface of the heat transfer plate on the evaporation surface side,
A cooling system for an electronic device, wherein a liquid supply guide for supplying the refrigerant is provided between the liquid level of the refrigerant and a height direction of the evaporation surface in parallel with the liquid level. In claim 1,
In the second evaporator of the second vaporization type cooling device, one opening of a steam / liquid pipe that forms a passage for the generated steam and a recovery passage for the refrigerant liquefied by the second condenser is provided above the liquid supply guide. A cooling system for electronic equipment, characterized in that the electronic equipment cooling system is provided. In claim 2,
A cooling system for electronic equipment, wherein a metal mesh is provided on an upper surface of the liquid supply guide. In claim 1,
A cooling system for electronic equipment, wherein a side plate is provided in an unconstrained portion of the liquid supply guide. In claim 1,
A cooling system for electronic equipment, wherein a vapor passage is provided in the liquid supply guide. In claim 1,
A cooling system for an electronic device, comprising a liquid reservoir buffer having an internal space communicating next to a second evaporator built in the thermal connector. In claim 6,
A cooling system for electronic equipment, wherein a partition plate for partially shielding a cross section of the communication portion is provided at a communication position between the second evaporator and the liquid storage buffer. In any one of Claims 1-7,
A cooling system for electronic equipment, characterized in that a horizontal steam / refrigerant pipe connected to the thermal connector of the second vaporization type cooling device and the second condenser in the top box are inclined with respect to a horizontal plane. .