JP2009193246A - Cooling system for electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling system of electronic equipment for efficiently cooling electronic equipment such as a computer and a server operating in precision and generating a large amount of heat, with small running costs. <P>SOLUTION: This cooling system 10 is provided with: a server room 12 where a plurality of servers 28 are arranged; an evaporator 34 for cooling the servers 28 by evaporating a coolant with heat generated by the servers 28; a cooling tower 38 for condensing the evaporated coolant; a compressor 54 for compressing the coolant to condense it; first circulation lines 46 and 48 connected between the evaporator 34 and the cooling tower 38 so that the coolant may naturally circulate; second circulation lines 46, 48, 58 and 60 connected so that the coolant may circulate in a refrigeration cycle including the evaporator 34 and the compressor 54 by branching the first circulation line, and connecting it to the compressor 54; and opening/closing valves 66 to 70 for switching the flow of the evaporated coolant by the first and second circulation lines. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic device cooling system, and more particularly to an electronic device cooling system for efficiently cooling an electronic device that requires precise operation of a computer, a server, and the like and generates a large amount of heat from itself.

  In recent years, with the improvement of information processing technology and the development of the Internet environment, the amount of information processing required has increased, and a data processing center for processing a large amount of various types of information has attracted attention as a business. In the server room of this data processing center, a large number of electronic devices such as computers and servers are installed in an integrated state, and are continuously operated day and night. In general, the rack mount method is the mainstream for installing electronic devices in a server room. The rack mount system is a system in which racks (casings) that divide and store electronic devices into functional units are stacked in a cabinet, and a large number of cabinets are arranged on the floor of a server room. Electronic devices that process such information are rapidly increasing in processing speed and processing capacity, and the amount of heat generated from the electronic devices is steadily increasing.

  On the other hand, these electronic devices require a certain temperature environment for operation, and the temperature environment for normal operation is set to be relatively low. Cause trouble. For this reason, the fact is that the air conditioning power for operating the air conditioner for cooling the server room is also greatly increasing, not only from the viewpoint of cost reduction in corporate management, but also from the viewpoint of conservation of the global environment, There is an urgent need to reduce air conditioning power.

  From such a background, as seen in Patent Document 1 and Patent Document 2, techniques for efficiently cooling electronic devices have been proposed. In Patent Document 1, a rear cover, a front cover, and a side-mounted cooling air subframe are attached to an electronic device, and a fan and a heat exchanger are provided in the cooling air subframe, so that It has been proposed to form a flow path through which cold air flows in a closed loop.

Further, in Patent Document 2, in a computer room air conditioning system including an electronic equipment storage rack group in which an evaporator and a fan are mounted, cooling air taken from outside flows into an internal space under the floor. The electronic device stored in the electronic device storage rack is cooled through the evaporator, and the condenser mounted on the back surface of the electronic device storage rack is cooled to flow in the space above or above the electronic device storage rack. However, it has been proposed to discharge the air through the ventilator. Moreover, although patent document 3 is not invention of cooling of an electronic device, the technique which circulates a refrigerant | coolant naturally between an evaporator and a condenser is introduced.
JP-T-2006-507676 JP 2004-232927 A JP 2007-127315 A

  By the way, the cooling system of the conventional electronic device can expect the effect of reducing the air-conditioning power of an air conditioner by using not only the cooling by an air conditioner but also the cooler directly attached to the electronic device. .

  However, while the air conditioning power is reduced, the operating power of the cooler directly attached to the electronic device is added, so that it is still not sufficient from the viewpoint of total energy saving. Accordingly, there is a demand for further reduction in running cost by energy saving.

  The present invention has been made in view of such circumstances, and can efficiently cool an electronic device that requires precise operation such as a computer and a server and generates a large amount of heat from itself at a low running cost. An object is to provide a cooling system for electronic equipment.

  In order to achieve the above object, the invention according to claim 1 is provided with an equipment room in which a plurality of electronic devices are arranged, and heat generated from the electronic devices provided in the vicinity of the plurality of electronic devices, respectively. An evaporator that cools the electronic device by vaporizing the refrigerant, a cooling tower that is provided at a higher position than the evaporator, cools the vaporized refrigerant by outside air, and condenses the refrigerant, and compresses the vaporized refrigerant A first circulation line connected so that the refrigerant naturally circulates between the compressor, the evaporator, and the cooling tower; and the first circulation line is branched and connected to the compressor. The second circulation line connected to circulate the refrigerant through the refrigeration cycle including the evaporator and the compressor, and the flow of the vaporized refrigerant is changed to the first circulation line and the second circulation line. With circulation line And switching means for changing Ri, provides a cooling system for an electronic apparatus, characterized in that it comprises a.

  The inventor paid attention to the fact that a stable amount of heat generation can be obtained by a plurality of electronic devices arranged in the equipment room. And if an evaporator is arranged in the vicinity of the electronic equipment, a natural circulation line in which the refrigerant circulates naturally between the evaporator and the cooling tower can be constructed, and a cooling system with low energy consumption can be obtained. It was. Furthermore, it has been found that if a refrigeration cycle is constructed using the refrigerant, a cooling system that consumes less energy and is stable can be constructed even when the amount of cooling in the natural circulation line is insufficient.

  The present invention has been made based on such knowledge, and while constructing a natural circulation type cooling system that circulates the refrigerant naturally between the evaporator and the cooling tower, the refrigerant is circulated by the compressor. Since the refrigeration cycle is constructed, energy consumption can be greatly reduced, and stable control can be performed. In particular, according to the present invention, since the same refrigerant is circulated in both the natural circulation type cooling system and the compression type refrigeration cycle, loss of heat due to heat exchange can be eliminated, and cooling efficiency can be improved.

  A second aspect of the present invention is characterized in that in the first aspect, a sensor for measuring the temperature and humidity of the outside air is provided, and the switching means switches the flow of the refrigerant based on a measured value of the sensor. According to the present invention, since the flow of the vaporized refrigerant is switched between the cooling tower and the compressor based on the temperature and humidity of the outside air, the natural circulation type cooling system using the cooling tower and the refrigeration cycle using the compressor are appropriately connected to the outside air. The temperature and humidity can be switched. Thereby, it is possible to always perform a cooling operation with good thermal efficiency.

  A third aspect of the present invention is characterized in that, in the first or second aspect, the cooling tower cools the refrigerant by spraying water together with blowing of the outside air. According to this invention, the cooling effect of a refrigerant | coolant can be heightened by performing watering.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the electronic device is a server, and the device room is a server room. The present invention can be applied to all electronic devices that require precise operation and generate a large amount of heat from itself. However, when the electronic device is a server and the device room is a server room, a further effect is expected. Because it can.

  As described above, according to the present invention, it is possible to efficiently cool an electronic device that requires precise operation such as a computer and a server and generates a large amount of heat from itself at a low running cost.

  Hereinafter, preferred embodiments of a cooling system for an electronic device according to the present invention will be described in detail with reference to the accompanying drawings. Note that an example of a server disposed in a server room will be described as an example of an electronic device.

(First embodiment)
FIG. 1 is a conceptual diagram showing a cooling system 10 for an electronic device according to a first embodiment of the present invention.

  As shown in FIG. 1, a server room 14 is formed in the building 12. An underfloor chamber 22 is formed on the back side of the floor surface of the server room 14. A plurality of air outlets (not shown) are arranged on the floor surface of the server room 14, and cool air from an air conditioner 78 (see FIG. 3) to be described later is blown out from the floor to the server room 14 through the underfloor chamber 22. The air outlet is preferably disposed in the vicinity of the front side of the server 28, and the cold air blown out is supplied to the server 28, whereby the server 28 is efficiently cooled. The structure of the building 12 is not limited to that shown in FIG. 1. For example, the server room 14 may be divided into a plurality of rooms, or the server room 14 may be provided over a plurality of floors.

  As shown in FIG. 2, a server rack 26 is disposed in the server room 14, and a plurality of servers 28 are stored in a stacked state in the server rack 26. The server rack 26 is preferably provided with a moving caster 24 so as to be movable. The server 28 includes a fan 30, and heat generated in the server 28 is exhausted from the server 28 by sucking and exhausting air in the server room 14 as indicated by an arrow 32. The arrangement of the server 28 is not limited to the above-described configuration, and a configuration in which the server rack 26 is not used is also possible.

  As shown in FIG. 1, an evaporator 34 is provided in the vicinity of the server 28. A cooling coil (not shown) is provided inside the evaporator 34, and the refrigerant liquid flowing in the cooling coil evaporates with hot air generated from the server 28, thereby removing vaporization heat from the surroundings and gasifying it. Thereby, the hot air discharged | emitted from the server 28 itself or the server 28 can be cooled.

  On the other hand, a cooling tower 38 is provided on the roof of the building 12. In the cooling tower 38, the spiral pipe 40 through which the above-described refrigerant flows is accommodated, and a sprinkling pipe 42 for sprinkling water into the spiral pipe 40 is provided above the spiral pipe 40. In addition, a fan 44 is provided above the sprinkling pipe 42. By taking outside air from the side opening of the cooling tower 38 and discharging it from the top opening, a counter current between the water to be sprinkled and the taken outside air is formed. Water sprayed is cooled. An inverter 43 is installed in the fan 44, and the inverter 43 is electrically connected to a control device 72 described later. The control device 72 is connected to a temperature sensor 45 and a pressure sensor 47 that measure the temperature and pressure of the liquid refrigerant at the outlet of the cooling tower 38, and controls the rotational speed of the fan 44 based on these measured values. For example, the rotational speed of the fan 44 is controlled so that the measured value of the temperature sensor 45 becomes the set temperature.

  A return pipe 46 and a supply pipe 48 are connected to the spiral pipe 40 of the cooling tower 38. The return pipe 46 and the supply pipe 48 are connected to the evaporator 34 disposed in the server room 14 through the underfloor chamber 22. Therefore, the refrigerant gas gasified by the evaporator 34 is naturally returned to the cooling tower 38 disposed above by passing through the return pipe 46, cooled and condensed by the cooling tower 38, and then the liquefied refrigerant liquid. Is naturally sent to the evaporator 34 disposed below by passing through the supply pipe 48. Thereby, a natural circulation line (corresponding to the first circulation line) in which the refrigerant naturally circulates between the cooling tower 38 and the evaporator 34, that is, a non-powered heat pipe in which the refrigerant is enclosed. . In this natural circulation line, the amount of heat generated from the server 28 is increased and a high-temperature refrigerant gas can be formed, so that the cooling temperature for condensing the refrigerant gas can be set higher. Can be condensed. In such a configuration, due to the rapid increase in the amount of heat generated from the server 28 in recent years, the high-temperature heat generated (discharged) from the server 28 is directly heat-exchanged with the refrigerant flowing through the evaporator 34 in a high-temperature state, thereby generating By promoting the evaporation of the refrigerant, it is possible to obtain transport power for transporting the evaporated refrigerant gas to the cooling tower 38 installed at a higher position than the evaporator 34. As the refrigerant to be used, chlorofluorocarbon or HFC (hydrofluorocarbon) as an alternative chlorofluorocarbon can be used. In addition, water can be used if it is used at a pressure lower than atmospheric pressure. Here, the expression “refrigerant” includes both a gaseous refrigerant gas and a liquid refrigerant liquid. In FIG. 1, the flow direction of the refrigerant gas is indicated by white arrows, The direction of flow is indicated by black arrows.

  The evaporator 34 is provided with a temperature sensor 50 for measuring the temperature of the hot air discharged from the server 28 after being cooled by the evaporator 34, and supplied to the cooling coil 36 at the inlet of the cooling coil 36. An expansion valve 52 is provided for adjusting the supply flow rate of the refrigerant. Then, the opening degree of the expansion valve 52 is automatically adjusted based on the temperature measured by the temperature sensor 50. Thereby, when the temperature of the wind after being cooled by the evaporator 34 becomes too lower than the set temperature, the opening degree of the expansion valve 52 is reduced and the supply flow rate of the refrigerant is reduced.

  The above is the driving method in winter when the outside air temperature is low, but the driving method is different in winter and summer. Next, the driving method in summer is described.

  The return pipe 58 is provided with a compressor 54. Although the position of the compressor 54 is the rooftop in this embodiment, it may be in the server room 14 other than the rooftop, for example. The compressor 54 is a device that compresses the refrigerant. For example, a centrifugal compressor that rotates the two-stage impellers 54A and 54B with a motor 54C and compresses the refrigerant with the centrifugal force is used. Moreover, not only a centrifugal compressor but a rotary compressor and a scroll compressor may be used.

  A branch return pipe 58 branched from the return pipe 46 is connected to the inlet of the compressor 54. A branch supply pipe 60 is connected to the outlet of the compressor 54, and the branch supply pipe 60 is connected to the return pipe 46 on the downstream side of the branch return pipe 58. The branch return pipe 58 and the branch supply pipe 60 and the return pipe 46 and the supply pipe 48 described above form a refrigerant circulation line (corresponding to the second circulation line), and the compressor 54 and the evaporator 34 are connected to each other. A refrigeration cycle is built. Thus, the refrigerant gas evaporated by the evaporator 34 is introduced into the compressor 54, compressed by the compressor 54, cooled by the cooling tower 38, condensed, and supplied to the evaporator 34.

  A gas / liquid separator 62 is disposed in the supply pipe 48. The gas-liquid separator 62 is for reliably separating the refrigerant gas from the condensed refrigerant liquid and for reliably sending the refrigerant liquid to the evaporator 34. The refrigerant gas separated by the gas-liquid separator 62 Is supplied to the middle portion of the compressor 54, that is, between the first-stage impeller 54A and the second-stage impeller 54B via the air supply pipe 64. FIG. 1 shows an example in which the economizer cycle is applied, but the present invention is not limited to this.

  The branch return pipe 58, the branch supply pipe 60, and the return pipe 46 are provided with on-off valves 66, 68, and 70, respectively. A valve 67 is provided on the inlet side of the gas-liquid separator 62 and a valve 69 is provided in the bypass pipe 63 of the gas-liquid separator 62. The on / off valves 66 to 70 are connected to the control device 72, and the on / off operation of the on / off valves 66 to 70 is performed by the control device 72. By opening / closing the on-off valves 66 to 70, the flow of the refrigerant gas is switched, and whether or not the refrigerant gas passes through the compressor 54 is selected. That is, switching between the first circulation line and the second circulation line is performed.

  The control device 72 is connected to an outside air sensor 74 that measures the temperature and humidity of outside air, and opens and closes the on-off valves 66 to 70 based on the measured value of the outside air sensor 74. For example, when the temperature of the outside air is low and the cooling capacity of the cooling tower 38 is large, the on-off valves 66 to 68 are closed and the on-off valves 69 and 70 are opened, and control is performed so that the refrigerant gas flows only through the cooling tower 38. On the other hand, when the temperature of the outside air is high and the capacity of the cooling tower 38 is insufficient, the on-off valves 69 and 70 are closed and the on-off valves 66 to 68 are opened to control the refrigerant gas to flow to the compressor 54. As a result, when the cooling capacity of the cooling tower 38 is high, such as in winter, the cost can be reduced by performing natural circulation using only the cooling tower 38. On the other hand, when the cooling capacity of the refrigerant is insufficient with only the cooling tower 38, such as in summer, a refrigeration cycle is constructed by flowing the refrigerant gas to the compressor 54, and thus the evaporator 34 performs sufficient cooling. be able to. As a result, the running cost can be minimized according to the cooling load required to condense the refrigerant gas, and various cooling modes can be taken.

  The following (1) to (3) are conceivable as specific switching control methods between the natural circulation and the refrigeration cycle.

(1) Switching method based on outside air wet bulb temperature and specific enthalpy The outside air sensor 74 measures the outside air temperature and humidity, and based on this, the control device 72 calculates the outside air wet bulb temperature or the outside air specific enthalpy. . When the calculated wet bulb temperature or specific enthalpy is larger than the set value for starting operation of the compressor 54, the compressor 54 is operated to perform the refrigeration cycle operation. The natural circulation operation is performed when the calculated wet bulb temperature or specific enthalpy is smaller than the set value for stopping the operation of the compressor 54. It should be noted that the setting value for starting operation of the compressor 54 is preferably larger than the setting value for stopping operation of the compressor 54 so that the operation is not frequently switched.

(2) Switching method by refrigerant load (or refrigerant flow rate) The control device 72 obtains the cooling load from the difference between the mass flow rate of the refrigerant and the specific enthalpy of the liquid refrigerant and the gas refrigerant. The mass flow rate of the refrigerant is obtained from the flow rate and specific gravity of the refrigerant, and the flow rate of the refrigerant is provided with an orifice 71 in the supply pipe 48 as shown in FIG. Find by measuring. On the other hand, the specific enthalpy between the liquid refrigerant and the gas refrigerant is obtained by the respective pressure and temperature (that is, the temperature sensor 45, the pressure sensor 47, the temperature sensor 75, and the pressure sensor 77). The control device 72 performs switching control as shown in FIG. 4 according to the combination of the refrigerant load thus obtained and the wet bulb temperature of the outside air obtained from the temperature and humidity measured by the outside air sensor 74. In FIG. 4, L1 is an operation line of the compressor 54, L2 is a stop line of the compressor 54, and is set outside of L1 (a side where the wet bulb temperature or the cooling load increases). In this example, the compressor 54 is stopped in the range X inside L1. And when L1 is exceeded, the driving | operation of the compressor 54 is started and the compressor 54 is drive | operated by rated refrigeration capacity in the range Y outside L2. And when it becomes smaller than L2, the compressor 54 is stopped.

  The specific enthalpy of the outside air may be used instead of the wet bulb temperature of the outside air. Further, although the accuracy is somewhat deteriorated, the refrigerant mass may be used instead of the refrigerant load. When the refrigerant flow rate is used, the switching may be performed with an allowance for the deterioration in accuracy.

(3) Switching method by pressure and temperature at the outlet of the cooling tower 38 Switching from the natural circulation to the refrigeration cycle is performed by the fan 44 at the maximum rotation speed and the temperature of the liquid refrigerant at the outlet of the cooling tower 38 (ie, the temperature sensor 45 The measured value is greater than a certain set temperature. For switching from the refrigeration cycle to natural circulation, a table for switching the pressure and temperature of the liquid refrigerant at the outlet of the cooling tower 38 is prepared in advance. That is, a temperature table for switching control is prepared for each pressure value. And based on the measured value of the pressure sensor 47, the switching temperature which performs switching control is calculated | required, and when the measured value of the temperature sensor 45 is smaller than switching temperature, switching control from a refrigerating cycle to natural circulation is performed.

  It is preferable to perform switching control between the natural circulation and the refrigeration cycle by any one of the methods (1) to (3).

  As described above, according to the cooling system 10 of the first embodiment, the refrigerant is provided between the evaporator 34 provided in the vicinity of the server 28 that generates a large amount of heat and the cooling tower 38 provided at a higher position. Since the cooling system that circulates naturally is constructed, the server 28 can be cooled at a low running cost.

  Further, according to the first embodiment, since the flow of the refrigerant gas is switched to the compressor 54, a compression refrigeration cycle including the evaporator 34 and the compressor 54 can be constructed, and natural circulation When the cooling amount is insufficient in the cooling system, the cooling amount can be ensured by the compression refrigeration cycle.

  Furthermore, according to the first embodiment, the refrigerant used in the natural circulation cooling system is also used as the refrigerant in the compression refrigeration system, thereby eliminating the need for a heat exchanger and using a heat exchanger or the like. Loss associated with heat exchange as in the case can be eliminated, and thermal efficiency can be improved.

(Second Embodiment)
FIG. 3 is a conceptual diagram showing a cooling system 100 for an electronic device according to the second embodiment of the present invention. The same members and configurations as those in the first embodiment are omitted.

  The cooling system 100 of the second embodiment is provided with an air conditioner 78 for cooling the server room 14 in the configuration of the cooling system 10 of the first embodiment, and the above-described refrigerant as a cooling heat source of the air conditioner 78. Is to be used.

  That is, as shown in FIG. 3, a machine room 80 is provided adjacent to the server room 14, and an air conditioner 78 is installed in the machine room 80. A suction duct 81 is connected to the suction port of the air conditioner 78, and the suction duct 81 extends to the server room 14 through a partition wall 82 that partitions the server room 14 and the machine room 80. Further, a blowout duct 83 is connected to the blowout port of the air conditioner 78, and this blowout duct 83 extends through the partition wall 82 to the underfloor chamber 22. Therefore, by driving the blower 86 of the air conditioner 78, the air in the server room 14 is taken into the air conditioner 78 through the suction duct 81 and cooled by the cooling unit 84, and then the underfloor chamber through the blowout duct 83. It blows out to 22 and is blown out to the server room 14 from the floor surface. At that time, it is preferable that the air blown out from the floor surface is sucked into the server 26 by forming the air outlet on the floor surface in the vicinity of the front surface of the server 26 (opposite the evaporator 34). An air conditioning return pipe 88 branched from the return pipe 46 and an air conditioning supply pipe 90 branched from the supply pipe 48 are connected to the cooling section 84 of the air conditioner 78 so that the refrigerant circulates through the cooling section 84. Configured.

  According to the cooling system 100 of the second embodiment configured as described above, the following effects can be exhibited in addition to the effects of the first embodiment described above. That is, since the above-described refrigerant is used as a cold heat source for the air conditioner 78 for cooling the server room 14 with cold air, the running cost for operating the air conditioner 78 can also be reduced. Further, by using together with the evaporator 34 that cools the server 28, the server is compared with an air conditioning system of a conventional method (a method in which the entire air is circulated and air-conditioned by floor blowing air conditioning disclosed in Japanese Patent Laid-Open No. 2004-232927). It is possible to suppress the occurrence of heat accumulation (locally high temperature part) in the room 14 and to increase the temperature of the supply air from the air conditioner 78 that air-conditions the whole. Therefore, in this embodiment, the evaporation temperature may be higher than in the conventional method, and the capacity of the cooling tower 38 can be fully utilized. Therefore, supplying the refrigerant of the natural circulation line to the cooling unit 84 of the air conditioner 78 contributes to both energy saving of the air conditioner 78 and performance of the cooling tower 38.

  Although the cooling systems 10 and 100 in the first and second embodiments described above have been described using the server 28 as an electronic device, the present invention is applicable to all electronic devices that generate a large amount of heat. Can be applied.

1 is a conceptual diagram illustrating a first embodiment of an electronic device cooling system according to the present invention; Explanatory drawing explaining a server and a server rack FIG. 3 is a conceptual diagram illustrating a second embodiment of a cooling system for an electronic device according to the present invention. Explanatory drawing explaining an example of the switching control method

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,100 ... Cooling system, 12 ... Building, 14 ... Server room, 22 ... Under floor chamber, 24 ... Caster, 26 ... Server rack, 28 ... Server, 30 ... Server fan, 32 ... Hot air, 34 ... Evaporator, 38 DESCRIPTION OF SYMBOLS ... Cooling device, 40 ... Spiral piping, 42 ... Spiral piping, 43 ... Inverter, 44 ... Cooling water fan, 45 ... Temperature sensor, 46 ... Return piping, 47 ... Pressure sensor, 48 ... Supply piping, 50 ... Temperature Sensors 52 ... Expansion valve 54 ... Compressor 58 ... Branch return pipe 60 ... Branch supply pipe 62 ... Gas-liquid separator 64 ... Air supply pipe 66-70 ... Open / close valve 71 ... Orifice 72 ... Control device 73 ... Differential pressure sensor 74 ... Outside air sensor 75 ... Temperature sensor 77 ... Pressure sensor 78 ... Air conditioner 79 ... Fan 80 ... Machine room 82 82 Bulkhead 84 ... Cooling unit 86 , 88 ... air conditioning supply pipe, 90 ... return air-conditioning piping

Claims (4)

An equipment room with a plurality of electronic devices,
An evaporator that is provided in the vicinity of each of the plurality of electronic devices and cools the electronic devices by evaporating a refrigerant with heat generated from the electronic devices;
A cooling tower that is provided at a higher position than the evaporator and cools and condenses the vaporized refrigerant with outside air;
A compressor for compressing the vaporized refrigerant;
A first circulation line connected so that the refrigerant naturally circulates between the evaporator and the cooling tower;
A second circulation line connected so that the refrigerant circulates in the refrigeration cycle including the evaporator and the compressor by branching the first circulation line and connecting to the compressor;
Switching means for switching the flow of the vaporized refrigerant between the first circulation line and the second circulation line;
An electronic device cooling system comprising:   2. The electronic apparatus cooling system according to claim 1, further comprising a sensor for measuring the temperature and humidity of the outside air, wherein the switching unit switches the flow of the refrigerant based on a measured value of the sensor.   The said cooling tower cools the said refrigerant | coolant by performing watering with the ventilation of the said external air, The cooling system of the electronic device of Claim 1 or 2 characterized by the above-mentioned.   The electronic device cooling system according to claim 1, wherein the electronic device is a server and the device room is a server room.

Images