JP6788551B2 - Cooling system - Google Patents

Description

The present invention relates to a cooling device, and more particularly to a device for cooling an electronic device.

With the development of information processing technology and communication technology, information and communication technology (ICT) services that combine these technologies are widely used. With the rapid development of ICT services in recent years, the heat generation amount and heat generation density (heat generation amount per device area) of electronic devices including ICT devices (information and communication devices) are rapidly increasing (high heat generation density). In the information and communication machine room and the data center that accommodate these electronic devices, it is said that about 40% of the total power consumption is spent on cooling the devices, and improvement of cooling efficiency is required. Further, the electronic device having a high heat generation density has a problem that if the cooling function is stopped during a power failure, the system reaches the guaranteed operating temperature as the room temperature rises.

FIG. 1 is a diagram illustrating an operation allowable time of an electronic device when the air conditioner device is stopped. Here, the time until the electronic device reaches the guaranteed operating temperature is defined as the allowable operating time. The guaranteed operating temperature of electronic devices differs depending on the standards to which they comply. For example, the upper limit of the guaranteed operating temperature of an electronic device installed in a rack in an equipment room controlled and maintained at 25 ° C. may be 50 ° C. As shown in FIG. 1, when the air conditioner in the equipment room is stopped due to a power failure, the temperature of the operating environment of the electronic equipment (temperature in the equipment room and rack temperature) starts to rise, and eventually reaches the guaranteed operating temperature (allowable temperature). The allowable temperature is exceeded. If the permissible temperature is exceeded (after the permissible operation time has passed), the electronic device will stop.

FIG. 2 is a diagram for explaining a power supply configuration in the information and communication machine room. In the information and communication machine room, in the event of a power failure, the ICT device 30 (also referred to as the electronic device 30) connected to the DC system via the rectifier 20 is generally backed up by the storage battery 40, but the air conditioner 50 or the like The cooling system of is an AC system connected to the commercial power 10 and basically does not hold a storage battery (FIG. 2A). When operating a cooling system such as an air conditioner in the equipment room even during a power outage, install an uninterruptible power supply (UPS) device 60 or storage battery 62 in the AC system (Fig. 2 (b)). Or, a method of using the DC system for air conditioning power via a converter can be considered. However, in order to operate the cooling system such as the air conditioner in the equipment room in the event of a power failure, there is a concern that the capital investment cost will increase. In particular, in the ICT device, the increase in heat generation density is remarkable as described above, and the system stops when the room temperature reaches the guaranteed operating temperature (allowable temperature) earlier than the storage battery of the DC system for the ICT device is exhausted. There is a problem that it ends up.

Conventionally, an air-cooled type and a liquid-cooled type have been used for cooling electronic devices, and the cooling efficiency has been improved by combining these. In recent years, immersion cooling using water cooling or another insulating liquid (cooling liquid) has been introduced (see, for example, Non-Patent Document 1). In immersion cooling, efficient local cooling is possible because the coolant directly cools the electronic device. In addition, in normal air-conditioning cooling, a fan is installed in the electronic device, but in immersion cooling, the fan is not required, which reduces the power consumption of the electronic device itself and improves reliability by reducing failures.

Katsutoshi Ishizuka, "Introduction to Illustrated Thermal Design of Electronic Equipment," Shuwa System, November 4, 2009, p. 42

However, in the prior art, a large amount of expensive UPS is required to continue cooling and extend the allowable operation time of the electronic device when the power is lost during a power failure. As described above, since about 40% of the electric power used in the communication machine room and the data center is used for cooling the device, the cost required for backing up the cooling device becomes enormous.

In addition, in the conventional technology, the entire room such as a data center or a storage box is cooled with respect to the stored electronic devices. Therefore, if a high heat generation density device is mixed in the room, the overall temperature is lowered. It is necessary to take measures such as cooling by cooling, enclosing a high heat generation density device with aisle capping (registered trademark), etc., or suppressing the amount of heat that can be mounted per rack, both of which increase the cost. However, there is a problem that the cooling efficiency is lowered.

The present invention has been made in view of such a problem, and an object of the present invention is a cooling device capable of ensuring a cooling capacity even when a power source is lost such as a power failure and extending an allowable operating time of an electronic device. Is to provide. The present invention also provides a cooling device such that the allowable operation time of an electronic device becomes longer than the storage battery holding time of the electronic device in the event of power loss such as a power failure.

In order to achieve such an object, one embodiment of the present invention cools an electronic device accommodating rack for accommodating electronic devices, a cooling tank accommodating a coolant, a pump for circulating the coolant, and the coolant. A cooling device including a heat exchanger and a chiller, wherein the cooling tank has an area for accommodating an electronic equipment accommodating rack in the lower part and an extra portion of the coolant in the upper part, and the electronic equipment is a coolant. It is immersed in the part other than the surplus part of the above and is connected to the storage battery for supplying power to the electronic device when the power is lost. When the power is lost, the pump, the heat exchanger and the chiller are stopped and cooled. The temperature of the electronic device while operating with the power supplied from the storage battery by the liquid is kept below the guaranteed operating temperature of the electronic device , and the allowable operation time of the electronic device is the electronic device. It is characterized in that it exceeds the holding time of the storage battery.

As described above, according to the present invention, in the event of a power failure, the coolant that has become hot due to the convection of the coolant moves to the upper part of the cooling tank so that the electronic device reaches the guaranteed operating temperature from the storage battery holding time. It is possible to delay.

It is a figure explaining the operation permissible time of the electronic device when the air conditioner is stopped. It is a figure for demonstrating the power source composition in an information communication machine room, (a) is a figure which shows the power source composition of a general equipment room, (b) is the device which provided the backup for the power source of an air conditioner. It is a power supply block diagram of a room. It is a block diagram of the cooling equipment which concerns on embodiment of this invention. It is a figure for demonstrating the cooling apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the cooling apparatus which concerns on embodiment of the invention, (a) is a figure for demonstrating the difference in the effect by the physical property of a coolant, and (b) is the figure for demonstrating the difference in the temperature rise due to the difference in the amount of a coolant. It is a figure which shows the difference, and (c) is a table which shows the physical property of a coolant.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or similar reference numerals indicate the same or similar elements, and the repeated description will be omitted. Further, in the following description, specific numerical examples, material names, etc. will be shown, but the present invention is not limited to this, and other numerical values and materials shall be applied without losing generality. Can be done.

The cooling device according to the embodiment of the present invention has a cooling tank, and the cooling tank contains an electrically insulating coolant. A rack containing electronic devices is housed in the cooling tank, and the electronic devices are immersed in the coolant. The coolant can be a fluorocarbon compound or synthetic oil having electrical insulation. The cooling tank is connected to a heat exchanger, and normally (when energized), a pump or the like is used to circulate the coolant to cool the electronic equipment. The rack is housed in the lower part of the cooling tank so that the coolant that has absorbed the heat radiation of the electronic device moves upward.

The cooling tank shall contain at least an amount of coolant (minimum amount of coolant) capable of immersing the electronic device and a surplus portion of the coolant (surplus coolant) that is surplus for immersing the electronic device. Can be done.

The minimum amount of coolant is determined according to the amount of electronic equipment installed. The amount of excess coolant is an amount capable of storing heat generated from an electronic device during a power failure, and is calculated from the power consumption of the electronic device and the time required to be maintained during a power failure.

Assuming that the rack contains the maximum number of electronic devices, the minimum amount of coolant for immersing the electronic devices is equivalent to the volume of the rack, so the cooling tank is at the top (in this case, above the rack). ) Is provided with an area for accommodating excess coolant.

The surplus portion of the coolant (surplus coolant) makes it possible to store the heat generated from the electronic device in the event of a power failure, and the allowable operating time of the electronic device can be longer than the storage battery holding time of the electronic device. Therefore, the cooling tank is filled with the coolant as needed, and in some cases, even if the excess coolant is accommodated, a space filled with air or the like is created.

3 and 4 are block diagrams of the cooling device according to the embodiment of the present invention. The cooling device of FIG. 3 includes a cooling tank 160, a pump 170 that circulates the coolant, and a heat exchanger 190 and a chiller 180 that cool the coolant. The cooling tank 160 can accommodate the electronic device accommodating rack 140 and the coolant 150. The electronic device accommodating rack can accommodate one or more electronic devices 30.

The cooling tank 160, the pump 170, the heat exchanger 190, and the chiller 180 are each connected to the commercial power 10 and are an AC system. On the other hand, the electronic device 30 is a DC system via a rectifier 20 connected to the commercial power 10, and a storage battery 40 for backup in the event of a power failure is provided between the rectifier 20 and the electronic device 30.

Referring to FIG. 4, the cooling tank 160 includes a region 165 for accommodating an electronic device accommodating rack in the lower portion and accommodating an excess portion of the coolant in the upper portion. The maximum number of electronic devices that can be accommodated in the electronic device storage rack is three. Therefore, the three electronic devices 30 (that is, the electronic device accommodating rack 140) housed in the electronic device accommodating rack are immersed in the minimum amount of coolant (the portion other than the excess coolant). The coolant contained in the region 165 above the three electronic devices 30 (that is, above the electronic device accommodating rack 140) is the surplus coolant (the portion other than the minimum coolant).

The power consumption of the three electronic devices 30 is 10 kW. The guaranteed operating temperature is 45 ° C.

The electronic device accommodating rack 140 can be made of steel and can have a volume of 420 L (width 600 mm × height 1000 mm × depth 700 mm).

The cooling tank 160 can be made of a metal such as steel or aluminum or a resin such as polycarbonate, and has a volume of 2000 L (width 1000 mm × height 2000 mm × depth 1000 mm).

The chiller 180 cools the water and supplies it to the heat exchanger 190. The chiller 180 can be, for example, a cold water chiller manufactured by Orion.

The heat exchanger 190 cools the circulating coolant 150 with the cold water supplied from the chiller 180. The heat exchanger 190 can be, for example, a plate heat exchanger manufactured by Alpha Label.

The coolant 150 is an insulating liquid, and for example, 3M's PF-5052, Fluorinert (registered trademark) FC-72, FC-770, FC-3282, FC-4, FC-43 and the like can be used. The coolant 150 circulates between the cooling tank 160 and the heat exchanger 190 by the pump 170. The temperature of the coolant 150 in the cooling tank 160 in the normal state (during power supply) is 20 ° C. For example, assuming that only 500 L of Florinate having a specific heat of 1050 J / kg K and a density of 25 ° C. of 1700 kg / m ³ is housed in the cooling tank 160, the coolant is radiated from the electronic device 30 having a power consumption of 10 kW. The temperature of 150 exceeds the guaranteed operating temperature (45 ° C.) 36 minutes after the pump 170 is stopped (power loss), but assuming that 1000 L of Florinate is contained in the cooling tank 160, the coolant 150 The temperature exceeds the guaranteed operating temperature (45 ° C.) 108 minutes after the loss of power, and the excess coolant extends the allowable operating time of the electronic device.

FIG. 5A is a diagram for explaining the difference in effect depending on the physical properties of the coolant. FIG. 5C is a table showing the physical properties of the coolant. FIG. 5A shows the temperature rise of fluorinert 43 and fluorinert 72 after the loss of power supply. The change in the temperature rise (Δt) of the coolant after the loss of power is slower in the dense fluorinert 43 (solid line) than in the less dense fluorinert 72 (single point broken line), and the denser coolant has a higher density. It can be seen that the allowable operating time of electronic devices can be extended.

FIG. 5B is a diagram showing a difference in temperature rise due to a difference in the amount of coolant. The state of the temperature rise after the loss of power supply when only 500 L of Fluorinert 43 is housed in the cooling tank 160 (one-dot dashed line) and when only 1500 L is housed (solid line) is shown. Compared to the case where the amount of the coolant contained in the cooling tank 160 is 500 L (amount slightly larger than the minimum amount coolant (420 L)), the amount is 1500 L (amount more than three times the minimum amount coolant). It can be seen that the allowable operating time of the electronic device can be extended.

10 Commercial power 20 Rectifier 30 ICT equipment, electronic equipment 40, 62 Storage battery 50 Air conditioner 60 Uninterruptible power supply 140 Electronic equipment storage rack 150 Coolant 160 Cooling tank 170 Pump 180 Chiller 190 Heat exchanger

Claims (2)

An electronic device storage rack for storing electronic devices, a cooling tank for storing coolant, and
A pump that circulates the coolant and
A heat exchanger and a chiller that cool the coolant,
It is a cooling device equipped with
The cooling tank has a lower portion for accommodating the electronic device accommodating rack and an upper portion for accommodating an excess portion of the coolant.
The electronic device is immersed in a portion of the coolant other than the surplus portion, and is connected to a storage battery for supplying electric power to the electronic device when power is lost.
When the power is lost, the pump, the heat exchanger, and the chiller are stopped, and the temperature of the electronic device while operating with the electric power supplied from the storage battery by the coolant is set to the electronic device. operation guaranteed temperature below be kept, and, Rukoto Do the allowable operating time of the electronic device retention time than by the battery of the electronic device,
A cooling device characterized by. The cooling device according to claim 1, wherein the amount of the cooling liquid contained in the cooling tank is more than three times the volume of the electronic device accommodating rack.

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