Cooling device, cooling system, and auxiliary cooling device for datacenter

Abstract

A cooling system for a data center is provided, in which a plurality of servers having exothermic electronic components is installed in a housing. The cooling system includes: a cooling circuit, a main cooling device to cool a cooling medium heated by electronic components, and an auxiliary cooling device to assist the main cooling device in cooling the cooling medium.

What is claimed is: 
     
       1. A cooling system for a data center, in which a plurality of servers having exothermic electronic components is installed in a housing, comprising:
 a circuit, in which a first cooling medium is circulated therethrough; 
 a main cooling device, which is connected with the electronic components through the circuit, and to which the first cooling medium heated by drawing heat from the electronic components is returned; and 
 an auxiliary cooling device, which is arranged on a return pipe of the circuit between the main cooling device and the electronic components to assist the main cooling device in cooling of the first cooling medium, 
 wherein the main cooling device comprises a compressor which compresses a second cooling medium by applying a pressure to the second cooling medium, a condenser which transports heat of the compressed second cooling medium to outside, thereby condensing the second cooling medium, an expansion valve which adiabatically expands the condensed second cooling medium, and an evaporator which removes the heat from the first cooling medium by the second cooling medium that is expanded and thereby having a temperature which is lowered; 
 wherein the auxiliary cooling device is configured to cool the first cooling medium flowing back to the main cooling device by radiating the heat of the first cooling medium to the atmosphere, and comprises a tank which stores the first cooling medium therein, and a first plurality of heat pipes which are adapted to cool or freeze the first cooling medium by radiating the heat of the first cooling medium to the atmosphere; 
 wherein the tank comprises a plurality of flow channels formed as grooves between ribs on a bottom of the tank, and the first cooling medium flows unidirectionally through the flow channels; 
 wherein the plurality of heat pipes comprises thermosiphons, in which a volatile and condensable working fluid is encapsulated in an air-tight fashion; 
 wherein first end portions of the thermosiphons are immersed into the first cooling medium in the flow channels of the tank to serve as an evaporation portion, and second end portions of the thermosiphons are exposed to the atmosphere to serve as a condensing portion; and 
 wherein the first plurality of heat pipes are arranged such that the volatile and condensable working fluid drops only gravitationally to unidirectionally restrict direction of transport of the heat. 
 
     
     
       2. The cooling system for a data center according to  claim 1 , further comprising:
 a heat exchanger, which is arranged on the circuit between the electronic components and the main and auxiliary cooling devices to exchange the heat of the electronic components and cold energy of the first cooling medium. 
 
     
     
       3. The cooling system for a data center according to  claim 1 , further comprising:
 a cooling tower, which is connected with the main cooling device to radiate heat of the main cooling device to the atmosphere. 
 
     
     
       4. The cooling system for a data center according to  claim 1 , further comprising:
 a mixing tank. 
 
     
     
       5. The cooling system for a data center according to  claim 4 , wherein:
 the mixing tank is divided into a plurality of mixing chambers, and adjoining mixing chambers are connected by a through hole. 
 
     
     
       6. The cooling system for a data center according to  claim 5 , further comprising:
 a first switching valve, which switches a route for feeding the cooling medium from the mixing tank to the electronic component between a route from said one of the mixing chamber to the electronic component, and a route from said another one of the mixing chamber to the electronic component; 
 a first pump, which is arranged between the first switching valve and the electronic component to feed the cooling medium to the electronic component; 
 a second switching valve, which switches a route for feeding the cooling medium from the mixing tank to the main cooling device between a route from said one of the mixing chamber to the main cooling device, and a route from said another one of the mixing chamber to the main cooling device; 
 a second pump, which is arranged between the second switching valve and the main cooling device to feed the cooling medium to the main cooling device; and 
 a third pump, which is arranged on a route between said one of the mixing chamber and the auxiliary cooling device to feed the cooling medium in said one of the mixing chamber to the auxiliary cooling device. 
 
     
     
       7. The cooling system for a data center according to  claim 1 , further comprising:
 a first switching valve, which returns the cooling medium heated by heat of the electronic components selectively to the main cooling device and the auxiliary cooling device; and 
 a second switching valve, which supplies the cooling medium to the electronic component selectively from the main cooling device and the auxiliary cooling device. 
 
     
     
       8. The cooling system for a data center according to  claim 7 , further comprising:
 a first pump, which is arranged on the circuit connecting the electronic component and the heat exchanger to circulate the cooling medium therethrough; 
 a second pump, which is arranged on the circuit connecting the heat exchanger and the main cooling device to circulate the cooling medium therethrough; and 
 a third pump, which is arranged on the circuit connecting the main cooling device and the cooling tower to circulate the cooling medium therethrough. 
 
     
     
       9. The cooling system for a data center according to  claim 1 , wherein the auxiliary cooling device further comprises:
 a heat insulating layer, which covers the tank to prevent the tank from being warmed by an external heat. 
 
     
     
       10. The cooling system for a data center according to  claim 9 , wherein the heat insulating layer comprises:
 an inner layer formed of an evacuated panel in which an internal pressure is reduced to be lower than an atmospheric pressure; and 
 an outer layer formed of heat insulating porous material. 
 
     
     
       11. The cooling system for a data center according to  claim 9 , wherein the auxiliary cooling device further comprises:
 a soil layer containing predetermined moisture and covering the tank; and 
 a second plurality of heat pipes which are buried in the soil layer at least partially to freeze the moisture in the soil layer by radiating the heat of the moisture unilaterally to the atmosphere, under the condition in which a temperature of the moisture in the soil layer is higher than an external temperature and the external temperature is lower than a predetermined temperature. 
 
     
     
       12. The cooling system for a data center according to  claim 11 , wherein:
 said second plurality of heat pipes comprise thermosiphons, in which a volatile and condensable working fluid is encapsulated air-tightly; 
 wherein one of end portions of the thermosiphons are buried in the soil layer to serve as an evaporating portion; and the other end portion of the thermosiphons are exposed to the atmosphere to serve as a condensing portion, and wherein the first plurality of heat pipes are arranged such that the condensed working fluid drops only gravitationally to unilaterally restrict the direction of transport of the heat. 
 
     
     
       13. The cooling system for a data center according to  claim 11 , wherein:
 a thickness of the soil layer is approximately 1 meter. 
 
     
     
       14. The cooling system for a data center according to  claim 13 , wherein:
 the material of the soil layer is selected from a group consisting of sand, loam and clay. 
 
     
     
       15. The cooling system for a data center according to  claim 14 , wherein a moisture content of the soil layer is kept within a range of 2.5 to 10% when the soil layer is formed of sand, a moisture content of the soil layer is kept within a range of 10 to 17.5% when the soil layer is formed of loam, and a moisture content of the soil layer is kept within a range of 17.5 to 25% when the soil layer is formed of clay. 
     
     
       16. The cooling system for a data center according to  claim 1 , wherein the auxiliary cooling device further comprises:
 a cold storage medium, which is sealed in the tank to be frozen by external cold energy entering into the tank through the thermosiphon; and 
 a heat exchanging tube, which is arranged around the evaporating portion of the thermosiphon, and at which the cold energy of the frozen cold storage medium in the tank is transferred to the cooling medium flowing therethrough. 
 
     
     
       17. The cooling system for a data center according to  claim 16 , wherein:
 the heat exchanging tube includes a coil heat exchanger formed by winding a hollow tube around the evaporating portion of the thermosiphon. 
 
     
     
       18. The cooling system for a data center according to  claim 17 , wherein:
 the material of the heat exchanging tube is selected from the group consisting of copper, copper alloy, aluminum, aluminum alloy, and synthetic resin. 
 
     
     
       19. The cooling system for a data center according to  claim 16 , wherein:
 the heat exchanging tube includes a U-shaped heat exchanger formed by bending a hollow tube into U-shape and arranged in the vicinity of the evaporating portion of the thermosiphon. 
 
     
     
       20. The cooling system for a data center according to  claim 1 , further comprising:
 an air conditioner, which is arranged in the housing to control the temperature in the housing thereby cooling the server; and 
 an assist heat pipe, which transports heat in the housing unilaterally to the atmosphere thereby assisting the air conditioner; and 
 wherein the assist heat pipe includes a thermosiphon, in which a volatile and condensable working fluid is encapsulated air-tightly; 
 one of end portions of the thermosiphon is situated in the housing above the server in a direction of gravitational force, and the other end portion of the thermosiphon is exposed to the atmosphere; and, 
 wherein the assist heat pipe is arranged such that the condensed working fluid drops only gravitationally to unilaterally restrict the direction of transport of the heat. 
 
     
     
       21. The cooling system for a data center according to  claim 1 , wherein the auxiliary cooling device is buried in the ground in a cold region where a freezing index is higher than 400 degree C.·day. 
     
     
       22. A process of cooling a data center, wherein the process comprises the steps of supplying the cooling medium heated by the electronic component, and the cooling medium cooled by the main cooling device or the auxiliary cooling device, to the mixing tank of the cooling system of  claim 4  to regulate the temperature thereof; and
 selectively supplying the cooling medium mixed in the mixing tank to the main cooling device and the auxiliary cooling device to be cooled, and also to the electronic component. 
 
     
     
       23. A process of cooling a data center, wherein the process comprises the steps of
 supplying the cooling medium heated by the electronic component to one of the mixing chambers connected with the electronic component; and 
 supplying the cooling medium cooled by the main cooling device or the auxiliary cooling device to another one of the mixing chambers of  claim 5  connected with the main cooling device and the auxiliary cooling device; and 
 gradually mixing the cooling medium heated by the electronic component, and the cooling medium cooled by the main cooling device or the auxiliary cooling device, in the mixing tank while flowing across the mixing chambers.