JP2011227829A - Cooling system for data center - Google Patents

Abstract

The present invention provides a data center cooling system that can reduce the temperature of a cooling medium for cooling a data center, thereby reducing the load and running cost of the cooling system.
A data center that cools the electronic device by taking heat generated in a large number of electronic devices that process data by a cooling medium whose temperature has been lowered by a cooler and releasing it to the outside. In the cooling system of 1, the cooling medium is circulated between the heat exchanger 6 that takes away heat generated from the electronic device 4 and the cooler 7, and the cooling pipe among the circulation pipes An auxiliary cooler 14 for releasing heat of the cooling medium into the atmosphere by a heat pipe 16 is provided on the inlet side of the cooler 7.
[Selection] Figure 1

Description

  The present invention relates to a cooling system that performs data processing and cools a data center including a large number of electric devices that generate heat when driven.

  As an example of a data center cooling system, it has been studied to cool a large number of heat-generating electronic devices housed in the data center using, for example, water whose temperature has been lowered by a chiller unit as a cooling medium. Since these electronic devices are always operated for data processing, this type of cooling system requires an enormous amount of water for cooling such electronic devices, and always uses a low-temperature cooling medium. It is necessary to secure. Therefore, the size of the chiller unit for cooling the cooling medium is increased, or the so-called load and running cost associated with the cooling increase. Therefore, it is desired to reduce the size of the device for cooling the data center and reduce the running cost.

  By the way, in Patent Document 1, an ice making pit for storing water is provided in the ground building or in the underground space, and the heat of the water is frozen in the air by a heat pipe to store the cold in winter. Described inventions are described.

JP-A-60-207877

  As described in Patent Document 1 described above, if the inside of the low-temperature warehouse is cooled by cold storage heat, the running cost of the chiller unit that cools the inside of the warehouse can be reduced in spring or summer. However, the technique described in Patent Document 1 is a technique for storing cold heat in winter or cold season by freezing water stored in an ice making pit by a heat pipe. Thus, conventionally, there is no function for lowering the temperature of the cooling medium used in the chiller unit, thereby reducing the load and running cost of the chiller unit, and there is still room for improvement.

  The present invention has been made paying attention to the above technical problem, and reduces the temperature of the cooling medium that cools the data center, thereby reducing the load and running cost of the cooling system. An object of the present invention is to provide a cooling system.

  In order to achieve the above object, according to the first aspect of the present invention, the cooling medium whose temperature is lowered by a cooler takes heat generated by a large number of electronic devices that process data and releases it to the outside. In the cooling system of the data center for cooling the electronic device by the above, a circulation line for circulating the cooling medium between the heat exchanger that takes away heat generated from the electronic device and the cooler, and the circulation pipe An auxiliary cooler for releasing the heat of the cooling medium into the atmosphere by a heat pipe is provided on the inlet side of the cooler in the passage.

  According to a second aspect of the present invention, in the first aspect of the invention, the auxiliary cooler includes a storage tank that temporarily stores the cooling medium, and the heat pipe has an evaporating portion that is cooled in the storage tank. A cooling system for a data center, wherein the cooling system is arranged so as to be immersed in a working medium and the condensing part is exposed to the upper atmosphere outside the storage tank.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, in the heat pipe, a working fluid that circulates and flows with evaporation and condensation is enclosed in an airtight container, and the liquid phase operation is performed by gravity. The data center cooling system includes a thermosyphon that recirculates a fluid to a lower end portion that is the evaporation portion of the sealed container.

  According to the first aspect of the present invention, the circulation line for circulating the cooling medium is formed between the heat exchanger that takes the heat of the electronic device and the cooler, and the inlet side of the cooler in the circulation line In addition, an auxiliary cooler provided with a heat pipe that dissipates heat of the cooling medium into the atmosphere is provided. In other words, an auxiliary cooler is provided in series with the cooler. In other words, the cooling medium whose temperature has increased due to the removal of heat from the electronic device is radiated to the atmosphere by the heat pipe, and the temperature is lowered. Then, the cooling medium whose temperature is lowered is introduced into the cooler. As a result, since the temperature of the cooling medium is lowered by the auxiliary cooler, the load on the cooler and the running cost can be reduced as compared with the case before the auxiliary cooler is provided. Moreover, since the load and running cost of the cooler can be reduced, the cooler can be downsized as compared with the conventional case. Furthermore, when the temperature of the cooling medium can be lowered to a predetermined temperature by the auxiliary cooler, for example, the temperature of the cooling medium supplied from the cooler to the electronic device can be lowered by the auxiliary cooler. In this case, the operation of the cooler can be stopped, and the load and running cost of the cooler can be reduced. Since the auxiliary cooler is configured to release heat of the cooling medium into the atmosphere by a heat pipe, the auxiliary cooler is a condenser for cooling the cooling medium such as a cooler. And mechanical devices such as a power source for operating this are not required. Therefore, the auxiliary cooler can have a simple configuration, and its maintenance can be unnecessary or reduced.

  According to the invention of claim 2, in addition to the same effect as that of the invention of claim 1, the auxiliary cooler includes a storage tank that temporarily stores the cooling medium, and the heat pipe is stored in the storage tank. The evaporating part is immersed in the cooling medium, and the condensing part is disposed outside the storage tank and exposed to the upper atmosphere. In other words, the heat of the cooling medium is transported by heat pipes and is radiated into the atmosphere so that the temperature is lowered. As a result, the auxiliary cooler does not require a mechanical device such as a condenser for cooling the cooling medium and a power source for operating the auxiliary medium, unlike the cooler. The maintenance management can be unnecessary or reduced.

  According to the invention of claim 3, in addition to the same effect as the effect of the invention of claim 1 or 2, the heat pipe includes a thermosiphon that recirculates the condensed working fluid to the evaporation section by gravity. In this thermosyphon, the evaporation part at the lower end is immersed in the cooling medium, and the condensation part is exposed to the atmosphere outside the storage tank. It can be limited or restricted in direction. In other words, the thermosyphon transports the heat of the cooling medium from the evaporating part to the condensing part due to the thermal diode characteristic in which the heat transport direction is limited to one direction, so that the working fluid enclosed in the sealed container When the portion for heating the portion and the portion for condensing the vaporized working fluid are reversed, heat flow is not generated. That is, it does not operate in the top heat mode. As a result, the thermosyphon does not take in the heat of the outside air and does not increase the temperature of the cooling medium inside the storage tank. In other words, an increase in the temperature of the cooling medium due to the so-called reverse flow of heat can be prevented or suppressed. When the temperature of the outside air becomes a predetermined temperature or lower, the thermosyphon can dissipate the heat of the cooling medium into the atmosphere and cool the cooling medium. By cooling the heat of the cooling medium by so-called air radiation, the load on the cooler can be reduced as compared with the case where an auxiliary cooler equipped with such a thermosyphon is provided. Moreover, the running cost of a cooler can be reduced. Furthermore, when the cooling medium can be cooled to a predetermined temperature or lower, the operation of the cooler can be stopped, and the running cost can be reduced.

It is a figure which shows typically an example of the cooling system of the data center which concerns on this invention.

  Next, the present invention will be specifically described with reference to the drawings. FIG. 1 schematically shows an example of a data center cooling system according to the present invention. The data center 1 includes a predetermined building 2, and at least a plurality of server racks 3 are provided in the room. In short, the building 2 is a so-called one for housing the server rack 3, and thus may be an appropriate one such as a construction building or a shipping container. Each server rack 3 accommodates a large number of servers. Each server is provided with a large number of electronic devices 4 that generate heat upon data processing on the substrate. Examples of the electronic device 4 include a CPU (Central Processing Unit) and a memory. Each electronic device 4 is in contact with a cold plate 5 that directly cools them by heat exchange so that heat can be transferred.

  The cold plate 5 is formed, for example, in a hollow plate shape, and a cooling medium flows through the hollow interior. Since the cold plate 5 needs to transfer heat between the inside and the outside, it is preferable that the cold plate 5 is made of a material having high thermal conductivity, such as copper or a copper alloy. Is preferred. The cold plate 5 is connected to the heat exchanger 6 so as to be able to transfer heat. More specifically, a first circulation pipe for circulating the cooling medium between the cold plate 5 and the heat exchanger 6 is formed. Has been.

  In short, the heat exchanger 6 performs heat exchange between a relatively high temperature fluid and a relatively low temperature fluid, and an appropriate heat exchanger such as a plate heat exchanger can be used. The cooling medium is a fluid that transports heat. For example, water or an aqueous solution in which an arbitrary rust preventive is dissolved in water or water, ethylene glycol, calcium chloride, or the like as a main component, So-called brine adjusted to have a freezing point of 0 ° C. or lower (sometimes referred to as antifreeze), or alternative CFCs such as R-134a can be used.

  The cooling medium whose temperature has risen due to heat exchange between the electronic device 4 and the cooling medium flowing inside the cold plate 5 flows through the first circulation pipe from the cold plate 5 toward the heat exchanger 6. The heat exchanger 6 is cooled by heat exchange. The cooling medium cooled in the heat exchanger 6 flows through the first circulation conduit from the heat exchanger 6 toward the cold plate 5 to cool the electronic device 4.

  The heat exchanger 6 is connected to the chiller unit 7 so that heat can be transferred. More specifically, a second circulation line for circulating the cooling medium is formed between the heat exchanger 6 and the chiller unit 7. In short, the chiller unit 7 is a so-called heat pump that moves heat by latent heat that accompanies compression / expansion of a refrigerant such as alternative chlorofluorocarbon. The chiller unit 7 has, as its main components, a compressor 8 that pressurizes and compresses the refrigerant, a condenser 9 that radiates heat of the compressed refrigerant to the outside, and is radiated to a low temperature and condensed. The expansion valve 10 expands the generated refrigerant, and the evaporator 11 absorbs the ambient heat from the expanded refrigerant.

  The cooling medium that has been heat-exchanged in the heat exchanger 6 and whose temperature has risen flows through the second circulation pipe described above from the heat exchanger 6 toward the chiller unit 7, and the heat in the evaporator 11 of the chiller unit 7. Is cooled by absorbing heat into the refrigerant. On the contrary, the cooling medium that has been heat-exchanged in the chiller unit 7, that is, cooled to a low temperature, flows through the second circulation pipe from the chiller unit 7 toward the heat exchanger 6, The exchanger 6 exchanges heat with the cooling medium that has deprived the electronic device 4 of heat. That is, the cooling medium cooled in the chiller unit 7 is transmitted to the cooling medium flowing in the first circulation pipe whose temperature has been raised by the heat exchanger 6 taking the heat of the electronic device 4 in the heat exchanger 6. The cooling medium is transmitted to the heat exchanger 6, and the cooled cooling medium flows through the first circulation pipe to cool the electronic device 4.

  In the example shown in FIG. 1, the condenser 9 of the chiller unit 7 is connected to a cooling tower 12 provided outside so as to be able to transfer heat. More specifically, for example, cooling water circulates between them. And in the condenser 9 of the chiller unit 7 mentioned above, the heat | fever of a refrigerant | coolant is thermally radiated with respect to the cooling water mentioned above. The heat of the refrigerant transmitted to the cooling water, that is, the heat of the electronic device 4 is radiated to the atmosphere by the fan 13 or the like in the cooling tower 12.

  In addition, an auxiliary cooler 14 according to the present invention is interposed in the middle of the second circulation pipe through which the cooling medium flows from the heat exchanger 6 toward the chiller unit 7. In other words, the auxiliary cooler 14 according to the present invention is provided in the second circulation line so as to be in series with the heat exchanger 6. The auxiliary cooler 14 temporarily stores a cooling medium that circulates and flows through the second circulation pipe described above, and heats the cooling medium temporarily stored in the storage tank 15 to the atmosphere. A heat pipe 16 for radiating heat is provided.

  The storage tank 15 is essentially a hollow container, into which a cooling medium whose temperature has been increased in the heat exchanger 6 is introduced and temporarily stored. Since the storage tank 15 temporarily stores the cooling medium, so-called waterproof measures are taken to prevent water from entering or penetrating the tank from the outside and preventing the cooling medium from leaking out. It is preferable that In addition, the storage tank temporarily stores a cooling medium serving as a so-called cold heat source in the heat exchanger 6 so as to be preliminarily stored therein. For example, it is preferably made of concrete. The storage tank 15 may be provided in the ground from the viewpoint of heat insulation. When the storage tank 15 is provided in the ground, the heat insulation effect can be improved compared with the case where it is provided on the ground surface.

  Further, a flow channel 17 may be provided inside or at the bottom of the storage tank 15 in order to cause the cooling medium introduced into the tank to flow in one direction. The flow channel 17 is essentially a so-called groove for allowing the cooling medium to flow in one direction. Therefore, the flow channel 17 may be formed by providing a plurality of ribs 18 inside the storage tank 15. A heat pipe 16 for transporting heat of the cooling medium to the flow channel 17 for flowing the cooling medium at a predetermined interval and dissipating it to the atmosphere is perpendicular to the horizontal plane of the cooling medium. Is provided.

  As described above, the heat pipe 16 is for radiating the heat of the cooling medium temporarily stored in the storage tank 15 to the atmosphere. Accordingly, one end 16a of the heat pipe 16 is temporarily stored in the storage tank 15, and is immersed in the cooling medium flowing in the flow channel described above. The other end 16b of the heat pipe 16 is arranged outside the storage tank 15 and exposed to the atmosphere. Further, a plurality of fins 16c for heat dissipation are provided at the other end 16b of the heat pipe 16. Therefore, one end portion of the heat pipe 16 is a so-called evaporation portion 16a in which the working fluid enclosed in the heat pipe 16 is heated to evaporate, and the latent heat of the working fluid evaporated at the other end portion is introduced into the atmosphere. It is the condensing part 16b which condenses a working fluid by radiating heat. In the example shown in FIG. 1, the heat pipe 16 is provided so that the longitudinal direction thereof is parallel to the direction of gravity. That is, the heat pipe 16 is provided vertically or substantially perpendicular to the horizontal plane of the cooling medium temporarily stored in the storage tank 15.

  The heat pipe 16 has a so-called thermal diode characteristic in which the direction of heat transport is limited or restricted to one direction. For example, a heat siphon (sometimes called a thermosiphon heat pipe) is used. can do. The thermosiphon 16 is configured, for example, by enclosing a working fluid in a state where a non-condensable gas such as air is deaerated in a predetermined hollow container (sometimes referred to as a container) that is airtight. . The container is, for example, a hollow tube, and since it is necessary to transfer heat between the inside and the outside, the hollow tube is preferably made of a material having high thermal conductivity. It is preferable to use a copper tube. A working fluid is a fluid that transports heat in the form of latent heat by being heated and evaporated, and radiating and condensing. The thermosiphon 16 is configured such that the working fluid condensed in the condensing unit 16b is returned to the evaporating unit 16a by gravity, and therefore does not operate in a so-called top heat mode.

  In the present invention, it is necessary to cool the cooling medium cooled by the chiller unit 7 in advance, or to sufficiently cool the cooling medium in place of the chiller unit 7, so that the thermosiphon 16 has, for example, an outside air temperature. It is preferably configured to operate when the temperature is 10 degrees Celsius or lower. Specifically, it is preferable to use ammonia having a boiling point of 10 ° C. or less or alternative chlorofluorocarbon such as R-134a for the working fluid of the thermosyphon 16. Moreover, in this invention, it is preferable that the quantity of the working fluid enclosed with the inside of the thermosiphon 16 is about 20-30 vol% of the internal volume.

  When the temperature of the outside air becomes lower than a predetermined temperature, for example, when the outside air temperature becomes 10 ° C. or less, the thermosyphon 16 performs heat transport in the form of latent heat of the working fluid from the evaporation unit 16a to the condensation unit 16b. The cooling medium can be cooled. Therefore, for example, when the outside air temperature is 10 degrees Celsius or lower and the temperature of the cooling medium in the storage tank 15 is 10 degrees Celsius or higher, the working fluid heated and evaporated in the evaporation section 16a has a relatively low temperature. The cooling medium is cooled by moving to the low pressure condensing part 16b and releasing heat in the air in the condensing part 16b. And the working fluid condensed with the heat radiation in the condensing part 16b is refluxed to the evaporation part 16a by gravity. On the other hand, when the temperature of the outside air becomes higher than the predetermined temperature, the thermosiphon 16 does not operate in the top heat mode as described above, so that the thermosiphon 16 takes in the heat of the outside air. Thus, the temperature of the cooling medium inside the storage tank 15 is not increased.

  When a so-called wick that recirculates the working fluid condensed by capillary action is used for the thermosyphon 16, a wick having a length corresponding to the length or depth at which the thermosyphon 16 is immersed in the cooling medium is It arrange | positions to the evaporation part 16a, ie, the lower end part of the thermosiphon 16. In FIG. By limiting the arrangement of the wicks in this way, the portion where the wicks are arranged can be used as the evaporation section 16a over the entire portion, and the thermal siphon 16 provided with the wicks also gives the thermal diode characteristics. be able to.

  Therefore, in the configuration described above, the heat generated in the electronic device 4 is taken away and cooled by the cooling medium that circulates and flows through the first circulation pipe. Then, the cooling medium whose temperature has been increased by taking the heat of the electronic device 4 flows through the first circulation pipe and is returned to the heat exchanger 6. In the heat exchanger 6, heat exchange is performed between the above-described cooling medium whose temperature has increased and the cooling medium cooled by the chiller unit 7 and flowing in the second circulation pipe and supplied to the heat exchanger 6. It is. In the heat exchanger 6, the cooling medium cooled by heat exchange flows through the first circulation pipe and is supplied to the electronic device 4 described above. On the other hand, the cooling medium whose temperature has increased by heat exchange in the heat exchanger 6 flows through the second circulation pipe, is supplied to the auxiliary cooler 14, and is temporarily stored in the storage tank 15.

  When the outside air temperature is equal to or lower than the predetermined temperature, the high-temperature cooling medium temporarily stored in the storage tank 15 is cooled by the heat siphon 16 being passively dissipated in the air. As a result, the so-called precooled cooling medium is returned to the chiller unit 7 in the auxiliary cooler 14. Therefore, the load and running cost of the chiller unit 7 can be reduced as compared with the case where the auxiliary cooler 14 is provided in series with the chiller unit 7. Specifically, compared with the case before the auxiliary cooler 14 is provided, the temperature decrease range of the cooling medium undertaken by the chiller unit 7 can be reduced, and the operation time of the chiller unit 7 can be reduced. Since the load on the chiller unit 7 can be reduced, the so-called carbon dioxide emission amount of the chiller unit 7 can be reduced. Moreover, a small chiller unit can be used compared with the past.

  When the temperature of the cooling medium can be lowered to a predetermined temperature by the auxiliary cooler 14, for example, the temperature of the cooling medium returned from the heat exchanger 6 to the chiller unit 7 by the auxiliary cooler 14 is given in degrees Celsius. When it can cool to around 10 ° C., the operation of the chiller unit 7 can be stopped. That is, without operating the chiller unit 7, the cooling medium can be sufficiently cooled only by in-air heat radiation by the thermosiphon 16 of the auxiliary cooler 14, and the electronic device 4 can be cooled by the cooled cooling medium. As a result, the load and running cost of the chiller unit 7 and the so-called carbon dioxide emission can be reduced. Moreover, a small chiller unit can be used compared with the past. Since the auxiliary cooler 14 does not require mechanical devices such as a condenser for cooling the cooling medium as compared with the chiller unit 7 or the like, the auxiliary cooler 14 can have a simple configuration. Moreover, it can be set as the apparatus which the maintenance management became unnecessary or reduced by this.

  DESCRIPTION OF SYMBOLS 1 ... Data center, 4 ... Electronic equipment, 6 ... Heat exchanger, 7 ... Chiller unit, 14 ... Auxiliary cooler, 16 ... Thermo siphon.

Claims (3)

In a cooling system of a data center that cools the electronic device by taking heat generated in a large number of electronic devices that process data by using a cooling medium whose temperature is lowered by a cooler and releasing the heat to the outside.
A circulation line for circulating the cooling medium between the cooler and a heat exchanger that removes heat generated from the electronic device;
A cooling system for a data center, wherein an auxiliary cooler for releasing heat of the cooling medium into the atmosphere by a heat pipe is provided on the inlet side of the cooler in the circulation line. The auxiliary cooler includes a storage tank for temporarily storing the cooling medium,
The heat pipe is disposed in a state in which the evaporation section is immersed in the cooling medium in the storage tank, and the condensation section is exposed to the upper atmosphere outside the storage tank. The data center cooling system according to claim 1. The heat pipe encloses a working fluid that circulates and flows with evaporation and condensation inside the sealed container, and returns the working fluid in a liquid phase to the lower end portion, which is the evaporation section, in the sealed container by gravity. The data center cooling system according to claim 1, further comprising a thermosiphon.

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