JP2021111660A - Immersion cooling system - Google Patents

Abstract

To provide an immersion cooling system capable of reducing running costs required for cooling a cooling target such as an electronic circuit board and introduction costs for the cooling system.SOLUTION: An immersion cooling system comprises: an immersion unit 2 that takes a low boiling point coolant F as a cooling element; and a cooling device 3 for cooling cooling water to be transmitted and supplied to the immersion unit 2. The immersion unit 2 comprises: a sealed container-shaped casing 5 for storing a cooling target B; and a condenser 10 disposed inside the casing 5. The cooling device 3 comprises: a pair of heat exchangers 19 disposed in a V shape; and an air blowing fan 20 for generating heat exchange air. The condenser 10 and the heat exchanger 19 are made to communicate with each other via a water transmission path 28. The condenser 10 liquefies coolant gas in a coolant gas chamber 8 while a circulation pump 29 forcibly makes cooling water cooled by the heat exchanger 19 circulate to the condenser 10.SELECTED DRAWING: Figure 1

Description

The present invention relates to an immersion cooling system for cooling an electronic circuit board represented by a motherboard.

This type of immersion cooling device is known, for example, in Patent Document 1. The liquid immersion cooling device of Patent Document 1 includes a closed container-shaped casing (casing) for storing an insulating low boiling point refrigerant and a condenser arranged in a gas phase region inside the casing. Immerse the printed plate in the internal liquid phase region to cool it. In addition, a straightening vane is placed between the peripheral wall of the housing and the printing plate, and the low boiling point refrigerant liquefied by the condenser is allowed to flow along the downflow chamber between the peripheral wall of the housing and the straightening vane, and the heat of the printing plate is generated. The gaseous low boiling point refrigerant that has been deprived of is made to flow along the ascending flow chamber between the rectifying plate and the printed plate. It is assumed that a refrigerating device that supplies the refrigerant liquid to the condenser is placed outside the housing, and the condenser is cooled by the evaporation action of the refrigerant liquid to liquefy the gaseous low boiling point refrigerant. There is.

Jitsukaisho 61-59350

The immersion cooling device of Patent Document 1 condenses the vaporized refrigerant gas with a condenser arranged inside the housing and returns it to the liquid phase region. It is assumed that the refrigerant sent from the refrigerating equipment circulates in the condenser, but in order to cool the printed circuit board, it is necessary to continuously operate the refrigerating equipment throughout the year, which increases the running cost. Unavoidable. In addition, for example, a large number of electronic circuit boards are used in a data center, but since a large-scale cooling system is required to cool a large number of electronic circuit boards, the introduction cost is enormous and the installation space is also large. It will be something like that. Further, in recent years, since a large number of CPUs and GPUs are mounted on an electronic circuit board, the amount of heat generated by the electronic circuit board is increased, and it is required that the cooling capacity of the cooling device can be further enhanced.

An object of the present invention is to provide a liquid immersion cooling system capable of reducing the running cost required for cooling an object to be cooled such as an electronic circuit board and the introduction cost of the cooling system.

The immersion cooling system of the present invention includes an immersion unit 2 having an insulating low boiling point refrigerant F as a cooling element, and a cooling device 3 for cooling the cooling water supplied to the immersion unit 2. The immersion unit 2 includes a closed container-shaped casing 5 that houses the cooling target B, and a condenser 10 that is arranged inside the casing 5 and liquefies the gasified low boiling point refrigerant F. The casing 5 includes a lower refrigerant liquid chamber 7 for storing the liquid low boiling point refrigerant F and an upper refrigerant gas chamber 8 for storing the gasified low boiling point refrigerant F, and is condensed in the refrigerant gas chamber 8. The vessel 10 is arranged. The cooling device 3 includes a cooling case 18, a pair of heat exchangers 19 arranged in a V shape inside the case 18, and a blower fan 20 that generates heat exchange air and brings it into contact with the heat exchanger 19. I have. The condenser 10 and the heat exchanger 19 are communicated with each other via a water supply channel 28 for supplying cooling water, and the cooling water is forced between the condenser 10 and the heat exchanger 19 in the middle of the water supply channel 28. A circulation pump 29 that circulates in the water is arranged. The refrigerant gas in the refrigerant gas chamber 8 is liquefied by the condenser 10 while supplying the cooling water cooled by the heat exchanger 19 to the condenser 10.

The cooling device 3 includes a chiller unit 16 including a chiller heat exchanger 27. As shown in FIG. 3, the chiller heat exchanger 27 is arranged on the air absorbing surface 19a side of the heat exchanger 19.

The cooling device 3 has an atomizing nozzle 34 arranged on the air absorbing surface 19a side of the heat exchanger 19, a water supply source 36 capable of pressurizing and supplying cooling water to the atomizing nozzle 34, and a water supply source 36 and an atomizing nozzle. It is provided with a water supply valve 35 arranged in a water supply channel between 34. As shown in FIG. 7, the cooling water passing through the heat exchanger 19 is cooled while spraying the mist generated by the atomizing nozzle 34 on the air sucked into the air suction surface 19a of the heat exchanger 19.

The water supply passage 28 includes a high temperature side water supply passage 28a for supplying the cooling water pressurized by the circulation pump 29 to the heat exchanger 19 and a low temperature side water supply passage 28b for supplying the cooling water after the heat exchange to the condenser 10. And have. Water temperature sensors 30 and 31 for detecting the temperature of the cooling water are provided in the high temperature side water supply channel 28a and the low temperature side water supply channel 28b, respectively. The cooling device 3 is provided with an outside air temperature sensor that detects the outside air temperature around the cooling device 3. The operating state of the cooling device 3 and the circulation pump 29 is controlled according to the detection results of the outside air temperature sensor and the water temperature sensors 30 and 31.

A backup water supply system is provided separately from the cooling device 3. The backup water supply system includes a water supply source 36 capable of pressurizing and supplying cooling water, an emergency water supply channel 43 for supplying the cooling water of the water supply source 36 to the cooling device 3, and a drainage channel for discharging the cooling water after heat exchange. It has 44. The emergency water supply channel 43 and the drainage channel 44 are connected in parallel to the high temperature side water supply channel 28a and the low temperature side water supply channel 28b of the cooling unit 15. In a state where the cooling device 3 has failed, the backup water supply system can be operated to supply the cooling water of the water supply source 36 to the condenser 10. Tap water, groundwater, river water, or the like can be used as the cooling water of the water supply source 36, and the cooling water is pressurized and supplied to the cooling unit 15 by a pump as needed.

The cooling device 3 includes a chiller 47 including a refrigerating device. The chiller 47 is connected in parallel to the high temperature side water supply channel 28a and the low temperature side water supply channel 28b of the cooling unit 15. The cooling unit 15 and the chiller 47 operate alternately according to the state of the outside air temperature.

A water-cooled heat exchanger 40 is arranged in the refrigerant liquid chamber 7 in a state of being immersed in the liquid of the low boiling point refrigerant F. The heat exchanger 40 is connected to the high temperature side water supply channel 28a and the low temperature side water supply channel 28b of the cooling unit 15 in parallel with the condenser 10 and is connected between the heat exchanger 40 and the low temperature side water supply channel 28b. An on-off valve 42 is provided in the water supply channel of the above. When necessary, cooling water is supplied from the low temperature side water supply channel 28b to the heat exchanger 40 to directly cool the low boiling point refrigerant F.

The cooling device 3 includes a plurality of cooling units 15. The plurality of cooling units 15 are connected in parallel to the high temperature side water supply channel 28a and the low temperature side water supply channel 28b.

A condensing pit 9 is formed to bulge outside the upper opening edge of the refrigerant liquid chamber 7, and the condenser 10 is arranged inside the condensing pit 9.

In the present invention, the immersion unit 2 includes a casing 5 in the shape of a closed container and a condenser 10 arranged in the refrigerant gas chamber 8 of the casing 5. Further, the cooling device 3 is provided with a pair of heat exchangers 19 arranged in a V shape and a blower fan 20. Further, the condenser 10 and the heat exchanger 19 are communicated with each other through the water supply channel 28, and the cooling water is forcibly circulated by the circulation pump 29 provided in the middle of the water supply channel 28. According to such an immersion cooling system, the refrigerant gas can be reliably liquefied by the condenser 10 only by operating the blower fan 20 and the circulation pump 29 of the heat exchanger 19, so that running when operating the immersion cooling system. The cost is low. Further, as compared with the case where the condenser 10 is operated by the heat of the refrigerant sent from the refrigerating equipment, it is sufficient to prepare the cooling device 3 having a simple structure, so that the cost for introducing the immersion cooling system can be reduced. In addition, there is an advantage that the space for arranging the cooling device 3 is reduced.

In the cooling device 3 including the chiller unit 16 including the chiller heat exchanger 27, the chiller heat exchanger 27 is arranged on the air absorbing surface 19a side of the heat exchanger 19. According to such a liquid immersion cooling system, even when the outside air temperature is high and the temperature of the cooling water supplied from the heat exchanger 19 to the condenser 10 cannot be sufficiently lowered, the chiller unit 16 is operated to operate the chiller unit 16. By sending the air cooled by the chiller heat exchanger 27 to the heat exchanger 19, the temperature of the cooling water supplied from the heat exchanger 19 to the condenser 10 can be sufficiently lowered. Therefore, it is possible to reliably liquefy the low boiling point refrigerant gas by the condenser 10, and further enhance the cooling capacity of the immersion cooling system to make the immersion cooling system compatible with the cooling target B having a large heat load. can.

In the cooling device 3 provided with the atomizing nozzle 34 arranged on the air suction surface 19a side of the heat exchanger, the water supply source 36 capable of pressurizing and supplying the cooling water, and the water supply valve 35, the atomizing nozzle 34 generates the cooling water. The cooling water passing through the heat exchanger 19 can be cooled while spraying the mist on the air sucked into the air suction surface 19a of the heat exchanger 19. According to such a liquid immersion cooling system, even when the outside air temperature is high, the outside air introduced into the heat exchanger 19 can be cooled by the evaporative action of the mist, and is sent from the heat exchanger 19 to the condenser 10. The refrigerant gas can be effectively liquefied by sufficiently lowering the temperature of the supplied cooling water to promote the liquefaction action of the condenser 10. Further, since the heat of vaporization of the mist ejected from the atomization nozzle 34 is used, the running cost of the immersion cooling system can be reduced.

An outside air temperature sensor for detecting the outside air temperature around the cooling device 3 is provided, and water temperature sensors 30 and 31 are provided in each of the high temperature side water supply passage 28a and the low temperature side water supply passage 28b constituting the water supply passage 28, and the outside air temperature sensor and the outside air temperature sensor are provided. The operating state of the cooling device 3 and the circulation pump 29 is controlled according to the detection results of the water temperature sensors 30 and 31. According to such a immersion cooling system, the blower fan 20 and the circulation pump 29 can be operated in a lean state according to the change in the outside air temperature and the temperature change in the cooling water, so that the running cost of the immersion cooling system can be increased. Can be further reduced.

In a liquid immersion cooling system provided with a backup water supply system separate from the cooling device 3, the emergency water supply channel 43 and the drainage channel 44 of the backup water supply system are parallel to the high temperature side water supply channel 28a and the low temperature side water supply channel 28b of the cooling unit 15. I tried to connect to. According to such a liquid immersion cooling system, even if the cooling device 3 fails, for example, the circulation pump 29 fails, the backup water supply system is operated and the cooling water of the water supply source 36 is condensed in the emergency water supply channel 43. It can be fed to the vessel 10 to effectively liquefy the refrigerant gas in the refrigerant gas chamber 8. Therefore, it is not necessary to stop the operation of the data center or the supercomputer, and the repair work of the failed portion of the cooling device 3 can be performed.

In the cooling device 3 including the chiller 47, the chiller 47 is connected in parallel to the high temperature side water supply channel 28a and the low temperature side water supply channel 28b of the cooling unit 15. Further, the cooling unit 15 and the chiller 47 are made to operate alternately according to the state of the outside air temperature. According to such a liquid immersion cooling system, the low-temperature cooling water cooled by the chiller 47 can be directly supplied to the condenser 10 to liquefy the refrigerant gas, so that the cooling water of the chiller 47 indirectly cools the heat exchange air. The condensation efficiency of the condenser 10 can be increased as compared with the liquid immersion cooling system. Therefore, the refrigerant gas can be effectively liquefied even when the outside air temperature is high. Further, since the cooling unit 15 may be operated in a situation where the outside air temperature is low, the running cost of the immersion cooling system can be reduced.

The water-cooled heat exchanger 40 arranged in the refrigerant liquid chamber 7 is connected to the high-temperature side water supply passage 28a and the low-temperature side water supply passage 28b of the cooling unit 15 in parallel with the condenser 10. .. According to such a liquid immersion cooling system, a low boiling point is obtained by supplying cooling water from the low temperature side water supply channel 28b to the heat exchanger 40, for example, in an emergency or when performing maintenance inside the liquid immersion unit 2. The temperature of the refrigerant F can be effectively lowered to a boiling point or lower, and the vaporization of the low boiling point refrigerant F can be stopped. Therefore, the safety of the immersion cooling system in an emergency can be improved, and the working time when performing maintenance inside the immersion unit 2 can be shortened.

The cooling device 3 is composed of a plurality of cooling units 15, and each cooling unit 15 is connected in parallel to the high temperature side water supply channel 28a and the low temperature side water supply channel 28b. According to such an immersion cooling system, the amount of cooling water that can be cooled per unit time can be increased, so that the liquid immersion cooling system that promotes the liquefaction action of the condenser 10 and can cope with the cooling target B having a large heat load without any trouble. Can be.

A condensing pit 9 was formed to bulge outside the upper opening edge of the refrigerant liquid chamber 7, and the condenser 10 was arranged inside the condensing pit 9. According to such an immersion cooling system, when the cooling target B housed in the refrigerant liquid chamber 7 is taken in and out, or when the inside of the immersion unit 2 is maintained, the maintenance work is performed without being disturbed by the condenser 10. It can be done easily.

It is a schematic front view which shows the principle structure of the immersion cooling system which concerns on Example 1 of this invention. It is a vertical sectional front view which shows the schematic structure of the immersion unit which concerns on Example 1. FIG. It is a vertical sectional front view which shows the schematic structure of the cooling device which concerns on Example 1. FIG. It is a schematic front view which shows the principle structure of the immersion cooling system which concerns on Example 2 of this invention. It is a schematic front view which shows the principle structure of the immersion cooling system which concerns on Example 3 of this invention. It is a schematic front view which shows the principle structure of the immersion cooling system which concerns on Example 4 of this invention. It is a vertical sectional front view which shows the schematic structure of the cooling device of the immersion cooling system which concerns on Example 5 of this invention. It is a vertical sectional front view which shows the schematic structure of the cooling device of the immersion cooling system which concerns on Example 6 of this invention.

(Example 1) Example 1 of the immersion cooling system according to the present invention is shown in FIGS. 1 to 3. The front-back, left-right, and up-down in this embodiment follow the crossing arrows shown in FIG. 1 and the front-back, left-right, and up-down notations in the vicinity of each arrow. As shown in FIG. 1, the immersion cooling system includes an immersion unit 2 having an insulating low boiling point refrigerant F as a cooling element and cooling water supplied to the immersion unit 2 arranged in the cooling booth 1. It is composed of a cooling device 3 or the like for cooling. This immersion cooling system can be applied to, for example, a data center or a supercomputer. When this immersion cooling system is applied to a data center, the cooling booth 1 is a server room, and the cooling device 3 is installed outside the server room (indoor or outdoor). The cooling booth 1 is preferably sealed to prevent the insulating low boiling point refrigerant F used in the immersion unit 2 from being accidentally discharged into the environment.

The immersion unit 2 includes a casing 5 in the shape of a closed container, and a condenser 10 arranged inside the casing 5 to liquefy the gasified low boiling point refrigerant F. More specifically, the immersion unit 2 includes a frame 4 assembled in a rectangular shape, a closed container-shaped casing 5, and an upper wall 6 for airtightly closing the upper opening of the casing 5, and below the inside of the casing 5. A refrigerant liquid chamber 7 for storing the liquid low boiling point refrigerant F is provided on the side, and a refrigerant gas chamber 8 for storing the gasified low boiling point refrigerant F is provided on the inner upper side of the casing 5. The low boiling point refrigerant F uses commercially available perfluorocarbon called Fluorinert (registered trademark), and in this embodiment, FC-72 of 3M Company is used as the low boiling point refrigerant F. The boiling point is 56 degrees Celsius (133 degrees Fahrenheit). The upper wall 6 is provided with a bellows 13 for preventing the pressure inside the refrigerant gas chamber 8 from exceeding the atmospheric pressure and becoming excessive, an emergency opening valve, and the like.

As shown in FIG. 2, condensation pits 9 are formed to bulge on the left and right outside the upper opening edge of the refrigerant liquid chamber 7, and the condenser 10 is arranged inside the condensation pits 9. The condenser 10 has a cross-fin tube structure and liquefies the gasified low boiling point refrigerant F. The fin plates of the condenser 10 are arranged at regular intervals in the front-rear direction in order to promote the flow of the liquefied low boiling point refrigerant F, and the refrigerant pipes are arranged in a meandering shape so as to penetrate the fin plates in the thickness direction. Has been done. The bottom wall 11 of the condensation pit 9 is inclined downward toward the refrigerant liquid chamber 7 in order to quickly return the droplets of the low boiling point refrigerant F dropped from the condenser 10 to the refrigerant liquid chamber 7. As shown in FIG. 2, the low boiling point refrigerant F is stored in the refrigerant liquid chamber 7 to the vicinity of the bottom wall 11, and a group of cooling target B such as a motherboard or an electronic circuit board is immersed in the liquid. It is held upright by the support member 12. Actually, a lotus metal plate such as a porous copper plate or a heat transfer body such as a sintered metal plate is arranged on the heat generating surface of the cooling target B composed of a group of electronic circuit boards, and a holder corresponding to the support member 12 is used. The frame is housed in a state where it is held upright at regular intervals (about 7 mm), the cooling target B is housed together with the frame at a predetermined distance from the bottom wall of the refrigerant liquid chamber 7, and the low boiling point refrigerant F is stored in the refrigerant liquid chamber 7. Is filled in to bring the cooling target B into an immersed state.

As shown in FIGS. 1 and 3, the cooling device 3 is composed of a pair of left and right cooling units 15 and a water-cooled chiller unit 16 attached to each cooling unit 15. Each cooling unit 15 includes a frame 17 assembled in a rectangular parallelepiped shape, an inverted trapezoidal cooling case 18 fixed to the front and rear surfaces of the frame 17, and a pair of cloths arranged in a V shape inside the case 18. It includes a heat exchanger 19 having a fin tube structure, a blower fan 20 that generates heat exchange air and brings it into contact with the heat exchanger 19. In this embodiment, the upper opening of the frame 17 is closed by the upper wall 21, the air guide cylinder 23 is arranged above the exhaust port 22 opened in the center thereof, and the blower fan 20 is housed therein. When the blower fan 20 is driven, the air in the space surrounded by the cooling case 18 and the heat exchanger 19 is discharged upward, so that the outside air is sucked from the air suction surface 19a side and passes through the heat exchanger 19 for cooling. Take away the heat of water.

Two cooling units 15 are prepared for one immersion unit 2, and the cooling water is cooled by a total of four heat exchangers 19, because the calorific value of the cooling target B in the immersion unit 2 is the amount of heat generated. Because it is big. Incidentally, the width × height × depth of one cooling unit 15 is 1300 × 1571 × 1470 mm, and its cooling capacity is 22 kW when the amount of cooling water is 80 L / min. However, when the temperature of the cooling water flowing into the heat exchanger 19 is 45 degrees C and the outside air temperature is 35 degrees C, the power consumption of the blower fan 20 at this time is 0.7 kW. Of the two cooling units 15, the air absorption surfaces 19a of the heat exchanger 19 facing the adjacent surfaces face each other at a short distance, so that the amount of air absorption is lower than that of the air absorption surfaces 19a facing the open surfaces on both the left and right sides. Tend. In order to avoid such a decrease in the amount of air absorption as much as possible, each heat exchanger 19 is arranged in a V-shaped inclined state. In this embodiment, the inclination angle of the heat exchanger 19 with respect to the horizontal plane was set to 75 degrees.

The chiller unit 16 includes a chiller main body 26 in which a compressor, an expansion valve, a condenser, an evaporator, etc. constituting a refrigerating device are integrated into one package, a chiller heat exchanger 27, and cooling cooled by the chiller main body 26. A feed pump 32 and the like for feeding water to the chiller heat exchanger 27 are provided, and the chiller heat exchanger 27 is arranged on the air absorption surface 19a side of the four heat exchangers 19. The refrigerant liquid supplied from the chiller main body 26 releases cold heat while passing through the chiller heat exchanger 27, and lowers the temperature of the air passing through each heat exchanger 19. The chiller unit 16 is operated in a situation where the outside air temperature is high to supplement the cooling capacity of the heat exchanger 19. The chiller main body 26 may be either an air-cooled type or a water-cooled type, and in this embodiment, the air-cooled chiller main body 26 is adopted.

In order to effectively liquefy the low boiling point refrigerant F in the condenser 10, the condenser 10 and the heat exchanger 19 are communicated with each other via a water supply passage 28 for supplying cooling water, and the middle portion of the water supply passage 28 Is provided with a circulation pump 29 that forcibly circulates cooling water between the condenser 10 and the heat exchanger 19. The water supply passage 28 includes a high temperature side water supply passage 28a for supplying the cooling water pressurized by the circulation pump 29 to the heat exchanger 19 and a low temperature side water supply passage 28b for supplying the cooling water after the heat exchange to the condenser 10. And have. The heat exchanger 19 of each cooling unit 15 is connected in parallel to the high temperature side water supply channel 28a and the low temperature side water supply channel 28b. In this way, if two heat exchangers 19 are connected in parallel to each of the water supply channels 28a and 28b, the amount of cooling water that can be cooled per unit time can be increased, so that the liquefaction action of the condenser 10 can be performed. By promoting this, it is possible to obtain a liquid immersion cooling system that can cope with the cooling target B having a large heat load without any trouble. The high temperature side water supply channel 28a is provided with the circulation pump 29 and a water temperature sensor 30 for detecting the temperature of the cooling water, and the low temperature side water supply channel 28b is provided with a water temperature sensor 31 for detecting the temperature of the cooling water after heat exchange. It is provided. In addition to the water temperature sensors 30 and 31, the immersion cooling system includes an outside temperature sensor that detects the outside air temperature around the cooling device 3, the temperature and level of the refrigerant liquid, and the temperature and pressure of the refrigerant gas. A sensor for detecting, a sensor for detecting the concentration of the refrigerant gas in the cooling booth 1, and the like are provided.

The liquid immersion cooling system configured as described above is used in combination with, for example, a server system to cool a cooling target B such as a motherboard or an electronic circuit board immersed in a low boiling point refrigerant F. The heat of the cooling target B is taken away by the boiling and vaporization of the low boiling point refrigerant F, and the vaporized gas of the low boiling point refrigerant F fills the refrigerant gas chamber 8. At this time, while supplying the cooling water cooled by the heat exchanger 19 to the condenser 10, the refrigerant gas in the refrigerant gas chamber 8 is liquefied by the condenser 10, thereby promoting the liquefaction action of the condenser 10. The refrigerant gas can be effectively liquefied.

In a situation where the outside air temperature is not so high, the refrigerant gas can be reliably liquefied by the condenser 10 simply by operating the blower fan 20 of the heat exchanger 19 and the circulation pump 29. The running cost is low. Further, as compared with the case where the condenser 10 is operated by the heat of the refrigerant sent from the refrigerating equipment, it is sufficient to prepare the cooling unit 15 having a simple structure, so that the cost for introducing the immersion cooling system can be reduced. In addition, there is an advantage that the space for arranging the cooling device 3 is reduced. Since the immersion unit 2 in the cooling booth 1 and the cooling device 3 installed outside the cooling booth 1 may be connected by the high temperature side water supply passage 28a and the low temperature side water supply passage 28b, cooling of a large airtight structure It is also advantageous in that it is not necessary to prepare booth 1. Condensation pits 9 are formed to bulge on the left and right outside the upper opening edge of the refrigerant liquid chamber 7, and the condenser 10 is arranged inside the condensation pits 9. Therefore, the cooling target B housed in the refrigerant liquid chamber 7 can be taken in and out, and the immersion unit 2 can be immersed. When performing maintenance on the inside of the condenser 10, the work can be performed without being disturbed by the condenser 10.

In a situation where the outside air temperature is high, such as in summer, the temperature of the cooling water supplied from the heat exchanger 19 to the condenser 10 may not be sufficiently lowered. In such a case, the temperature of the cooling water supplied from the heat exchanger 19 to the condenser 10 by operating the chiller unit 16 and sending the air cooled by the chiller heat exchanger 27 to the heat exchanger 19. Can be sufficiently reduced. Therefore, the low boiling point refrigerant F can be reliably liquefied by the condenser 10, and the cooling capacity of the immersion cooling system can be further enhanced to make the immersion cooling system compatible with the cooling target B having a large heat load. can. Further, the cooling device 3 is composed of a plurality of cooling units 15, and each cooling unit 15 is connected in parallel to the high temperature side water supply passage 28a and the low temperature side water supply passage 28b to reduce the amount of cooling water that can be cooled per unit time. Since it can be enhanced, it is possible to promote the liquefaction action of the condenser 10 to obtain a liquid immersion cooling system that can cope with the cooling target B having a large heat load without any trouble.

The operating states of the heat exchanger 19 and the chiller unit 16 are controlled by a control device (not shown), and the blower fan 20 is controlled according to the detection results of the outside air temperature sensor (not shown) and the water temperature sensors 30 and 31. , The operating state of the circulation pump 29, the chiller body 26, and the feed pump 32 is optimized. By optimizing the operating state of each device 20, 29, 26, 32 in this way, each device 20, 29, 26, 32 can be operated in a lean state, so that the running of the immersion cooling system can be performed. The cost can be further reduced.

As described above, according to the liquid immersion cooling system provided with the heat exchanger 19 and the chiller unit 16, the heat exchanger 19 and the chiller unit 16 can be operated at the same time in a situation where the outside air temperature is high such as in summer. , The air cooled by the chiller heat exchanger 27 can be sent to the heat exchanger 19, and the temperature of the cooling water supplied from the heat exchanger 19 to the condenser 10 can be sufficiently lowered. Therefore, the liquefaction action of the condenser 10 can be promoted to more effectively liquefy the low boiling point refrigerant gas. Further, even when the heat load of the cooling target B is large, it can be dealt with without any trouble by operating the chiller unit 16 intermittently.

(Example 2) FIG. 4 shows an immersion cooling system according to the second embodiment. The cooling device 3 in this embodiment is basically the same as the immersion cooling system of the first embodiment, but a water-cooled heat exchanger 40 is arranged in the refrigerant liquid chamber 7, and a branch is branched from the water supply channel 28. It differs from the liquid immersion cooling system of the first embodiment in that a water supply valve (opening / closing valve) 42 is provided at a branch portion of the water supply channel 41. Although only one of the cooling units 15 is shown in FIG. 4, the immersion cooling system is composed of two cooling units 15 and a chiller unit 16 attached to each cooling unit 15 as in the first embodiment. There is.

As described above, according to the immersion cooling system in which the water-cooled heat exchanger 40 is arranged in the refrigerant liquid chamber 7, the cooling water is used, for example, in an emergency or when the inside of the immersion unit 2 is to be maintained. By feeding the low boiling point refrigerant F from the low temperature side water supply channel 28b to the heat exchanger 40, the temperature of the low boiling point refrigerant F can be effectively lowered to the boiling point or lower, and the vaporization of the low boiling point refrigerant F can be stopped. Therefore, the safety of the immersion cooling system in an emergency can be improved, and when the inside of the immersion unit 2 is maintained, the casing 5 can be opened in a short time to shorten the working time. In the state where the immersion cooling system is normally operated, the water supply valve 42 is closed.

(Example 3) FIG. 5 shows an immersion cooling system according to the third embodiment. The cooling device 3 in this embodiment is basically the same as the liquid immersion cooling system of the first embodiment, but is provided with a backup water supply system in case the circulation pump 29 fails or the like. It is different from the immersion cooling system of 1. The backup water supply system includes a water supply source 36 capable of pressurizing and supplying cooling water, an emergency water supply channel 43 connecting the water supply source 36 and the low temperature side water supply channel 28b, and a drainage channel 44 branched from the high temperature side water supply channel 28a. , An on-off valve 45 and an on-off valve 46. The on-off valve 45 is provided in the high-temperature side water supply channel 28a and the low-temperature side water supply channel 28b, respectively, and the on-off valve 46 is provided in the emergency water supply channel 43 and the drainage channel 44, respectively. The emergency water supply channel 43 is connected to the downstream side of the on-off valve 45 of the low-temperature side water supply channel 28b, and the drainage channel 44 is connected to the upstream side of the on-off valve 45 of the high-temperature side water supply channel 28a. As the cooling water of the water supply source 36, tap water, groundwater, river water, etc. can be pressurized and fed by a pump, but it is preferable to use groundwater that is not easily affected by changes in the temperature of the outside temperature, and a plurality of groundwaters are used. A water source may be used together.

When the immersion cooling system is operated in the normal state, the on-off valve 46 on the backup water supply system side is closed, and the on-off valve 45 on the water supply channel 28 side is open. However, when the circulation pump 29 fails or the drive power supply of the cooling unit 15 is in a power failure state, the on-off valve 46 on the backup water supply system side is opened, and the on-off valve 45 on the water supply channel 28 side is closed. , The cooling water supplied from the water supply source 36 is supplied to the condenser 10. The cooling water after heat exchange is discharged to the outside of the cooling booth 1 through the drainage channel 44. According to the liquid immersion cooling system configured as described above, even if the cooling device 3 fails, for example, the circulation pump 29 fails, the backup water supply system is operated and the cooling water of the water supply source 36 is used in an emergency. The refrigerant gas in the refrigerant gas chamber 8 can be effectively liquefied by supplying the refrigerant gas to the condenser 10 through the water supply channel 43. Therefore, it is not necessary to stop the operation of the data center or the supercomputer, and the repair work of the failed portion of the cooling device 3 can be performed.

(Example 4) FIG. 6 shows an immersion cooling system according to the fourth embodiment. In the cooling device 3 according to the fourth embodiment, in addition to the pair of cooling units 15, a chiller 47 connected in parallel to the high temperature side water supply channel 28a and the low temperature side water supply channel 28b is provided. Specifically, the water supply channel 48 of the chiller 47 is connected to the low temperature side water supply channel 28b, the return water supply channel 49 of the chiller 47 is connected to the high temperature side water supply channel 28a, and the feed is sent between the feed pump 32 and the low temperature side water supply channel 28b. A check valve 50 is provided in the water channel 48. Further, an on-off valve 51 and a check valve 52 are provided in the low-temperature side water supply channel 28 to prevent the low-temperature cooling water supplied from the chiller 47 from flowing to the cooling unit 15 side. Further, an on-off valve 53 is provided in the return water supply channel 49 so that the cooling water after heat exchange is returned to the chiller 47. The chiller 47 of this embodiment has the same configuration as the chiller main body 26 of the first embodiment.

In the liquid immersion cooling system according to the fourth embodiment, when the outside temperature is high, the chiller 47 is operated and the low-temperature cooling water cooled by the chiller 47 is supplied to the condenser 10 to supply the refrigerant gas. Can be effectively liquefied. When the outside air temperature is low, the cooling unit 15 is operated to liquefy the refrigerant gas. That is, the cooling unit 15 and the chiller 47 are selectively operated according to the state of the outside air temperature. In this way, when the low-temperature cooling water cooled by the chiller 47 is directly supplied to the condenser 10 to liquefy the refrigerant gas, the heat exchange air is indirectly cooled by the cooling water of the chiller unit 16 according to the first embodiment. The condensation efficiency by the condenser 10 can be increased as compared with the liquid immersion cooling system. Therefore, the refrigerant gas can be effectively liquefied even when the outside air temperature is high. Further, since the cooling unit 15 may be operated in a situation where the outside air temperature is low, the running cost of the immersion cooling system can be reduced.

(Example 5) FIG. 7 shows an immersion cooling system according to the fifth embodiment. In the cooling device 3 in the fifth embodiment, the chiller unit 16 in the first embodiment is omitted. Specifically, the cooling device 3 includes a pair of cooling units 15, and heat exchangers 19 are arranged in a V shape in each cooling unit 15, and mist is formed on the air absorbing surface 19a side of each heat exchanger 19. The conversion nozzle 34 is arranged. The atomizing nozzle 34 is connected to a water supply source 36 capable of pressurizing and supplying cooling water via a water supply channel, and a water supply valve 35 is provided in the middle of the water supply channel. The cooling water supplied from the water supply source 36 is mist-ized by the atomizing nozzle 34 and sprayed onto the air sucked into the air suction surface 19a of the heat exchanger 19. According to such a liquid immersion cooling system, the air passing through the heat exchanger 19 can be cooled by the evaporative action of the mist ejected from the atomization nozzle 34, so that the same as the liquid immersion cooling system in which the chiller unit 16 is used in combination is used. Even in a situation where the outside air temperature is high, such as in summer, the temperature of the cooling water supplied from the heat exchanger 19 to the condenser 10 is sufficiently lowered to promote the liquefaction action of the condenser 10 to promote the refrigerant gas. Can be effectively liquefied. Further, since the heat of vaporization of the mist ejected from the atomization nozzle 34 is used, the running cost of the immersion cooling system can be reduced. As in the third embodiment, tap water, groundwater, river water, or the like can be used as the water supply source.

(Example 6) FIG. 8 shows the immersion cooling system according to the sixth embodiment. A heat exchanger 19 and a blower fan 20 were provided in each cooling unit 15 of the cooling device 3 in this embodiment, and the chiller unit 16 and the atomizing nozzle 34 were not used. Such a simple liquid immersion cooling system is suitable for use in a server system installed in a rural area or environment where the outside air temperature does not rise even in summer, and the liquid immersion is sufficient because the chiller unit 16 and the atomization nozzle 34 can be omitted. The installation cost and running cost of the cooling system can be significantly reduced.

In the above embodiment, in order to make it easier to understand the principle structure of the immersion cooling system, the combination of one immersion unit 2 and a cooling device 3 provided with two cooling units 15 has been described, but a large amount In a data center or the like where an electronic circuit board is used, it is assumed that the immersion cooling system is used as a combination of a large number of groups of immersion units 2 and a large number of groups of cooling devices 3. Two blower fans 20 of the cooling unit 15 may be provided corresponding to the individual heat exchangers 19. Further, the blower fan 20 may be in the form of supplying air toward the air suction surface 19a of the heat exchanger 19.

2 Immersion unit 3 Cooling device 7 Refrigerant liquid chamber 8 Refrigerant gas chamber 9 Condensing pit 10 Condenser 15 Cooling unit 16 Chiller unit 19 Heat exchanger 19a Blower surface 20 Blower fan 27 Chiller heat exchanger 28 Water supply channel 28a High temperature side feed Water channel 28b Low temperature side water supply channel 29 Circulation pump 30 Water temperature sensor 31 Water temperature sensor 34 Atomization nozzle 35 Water supply valve 36 Water supply source 40 Heat exchanger 42 On / off valve (water supply valve)
43 Emergency water supply channel 44 Drainage channel 47 Chiller F Low boiling point refrigerant B Cooling target

Claims (9)

It is equipped with an immersion unit (2) having an insulating low boiling point refrigerant (F) as a cooling element, and a cooling device (3) for cooling the cooling water supplied to the immersion unit (2).
The immersion unit (2) is arranged inside the casing (5) in the shape of a closed container for accommodating the object to be cooled (B) and the casing (5), and is a condensation that liquefies the gasified low boiling point refrigerant (F). Equipped with a vessel (10)
The casing (5) has a lower refrigerant liquid chamber (7) for storing a liquid low boiling point refrigerant (F) and an upper refrigerant gas chamber (8) for storing a gasified low boiling point refrigerant (F). The condenser (10) is arranged in the refrigerant gas chamber (8).
The cooling device (3) includes a cooling case (18), a pair of heat exchangers (19) arranged in a V shape inside the case (18), and a heat exchanger (19) that generates heat exchange air. It is equipped with a blower fan (20) that comes into contact with 19).
The condenser (10) and the heat exchanger (19) are communicated with each other via a water supply channel (28) for supplying cooling water, and the cooling water is condensed in the middle of the water supply channel (28) (10). ) And the heat exchanger (19), a circulation pump (29) that forcibly circulates is arranged.
Immersion characterized in that the refrigerant gas in the refrigerant gas chamber (8) is liquefied by the condenser (10) while supplying the cooling water cooled by the heat exchanger (19) to the condenser (10). Cooling system. The cooling device (3) comprises a chiller unit (16) including a chiller heat exchanger (27).
The immersion cooling system according to claim 1, wherein the chiller heat exchanger (27) is arranged on the air absorbing surface (19a) side of the heat exchanger (19). The cooling device (3) has an atomizing nozzle (34) arranged on the air absorbing surface (19a) side of the heat exchanger (19) and a water supply source capable of pressurizing and supplying cooling water to the atomizing nozzle (34). (36) and a water supply valve (35) arranged in the water supply channel between the water supply source (36) and the atomizing nozzle (34).
Claim 1 for cooling the cooling water passing through the heat exchanger (19) while spraying the mist generated by the atomizing nozzle (34) on the air sucked into the air suction surface (19a) of the heat exchanger (19). The liquid immersion cooling system described in. The water supply channel (28) supplies the cooling water pressurized by the circulation pump (29) to the heat exchanger (19) on the high temperature side water supply channel (28a), and the cooling water after the heat exchange is condensed (10). ) Is equipped with a low-temperature side water supply channel (28b).
Water temperature sensors (30/31) for detecting the temperature of the cooling water are provided in the high temperature side water supply channel (28a) and the low temperature side water supply channel (28b), respectively.
The cooling device (3) is provided with an outside air temperature sensor that detects the outside air temperature around the cooling device (3).
The liquid according to any one of claims 1 to 3, which controls the operating state of the cooling device (3) and the circulation pump (29) according to the detection results of the outside air temperature sensor and the water temperature sensor (30/31). Immersion cooling system. It is equipped with a backup water supply system in addition to the cooling device (3).
The backup water supply system includes a water supply source (36) capable of pressurizing and supplying cooling water, an emergency water supply channel (43) for supplying the cooling water of the water supply source (36) to the cooling device (3), and after heat exchange. It is equipped with a drainage channel (44) that drains the cooling water of
The emergency water supply channel (43) and the drainage channel (44) are connected in parallel to the high temperature side water supply channel (28a) and the low temperature side water supply channel (28b) of the cooling unit (15).
The liquid immersion cooling system according to claim 4, wherein the backup water supply system can be operated to supply the cooling water of the water supply source (36) to the condenser (10) in a state where the cooling device (3) has failed. The cooling device (3) is equipped with a chiller (47) configured to include refrigeration equipment.
The chiller (47) is connected in parallel to the high temperature side water supply channel (28a) and the low temperature side water supply channel (28b) of the cooling unit (15).
The immersion cooling system according to claim 4, wherein the cooling unit (15) and the chiller (47) operate alternately according to the state of the outside air temperature. A water-cooled heat exchanger (40) is arranged in the refrigerant liquid chamber (7) in a state of being immersed in the liquid of the low boiling point refrigerant (F).
The heat exchanger (40) is connected to the high temperature side water supply channel (28a) and the low temperature side water supply channel (28b) of the cooling unit (15) in parallel with the condenser (10) to exchange heat. An on-off valve (42) is provided in the water supply channel between the vessel (40) and the low temperature side water supply channel (28b).
4. Liquid immersion cooling system. The cooling device (3) is equipped with a plurality of cooling units (15).
The immersion cooling system according to any one of claims 4 to 7, wherein a plurality of cooling units (15) are connected in parallel to the high temperature side water supply channel (28a) and the low temperature side water supply channel (28b). .. 6. Immersion cooling system.

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