Cooling system for electronic equipment

• US 4,729,424 A
• Filed: 04/30/1987
• Issued: 03/08/1988
• Est. Priority Date: 04/05/1985
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Okano, Minoru, Mizuno, Tsukasa
• Primary Examiner(s): Cline, William R.
• Assistant Examiner(s): Ford, John K.
• Application Number:
  US07/052,174
• Time in Patent Office: 313 Days
• Field of Search: 165/30, 165/921, 165/80.4, 165/80.5, 236/78 B, 236/1 EA, 62/201, 62/196.1, 62/228.5, 62/175, 62/272, 357/82, 361/382, 361/381, 174/15 R
• US Class Current: 165/261
• CPC Class Codes: F25D 17/02 for circulating liquids, e.g. brine
• CPC Class Codes: G06F 1/20 Cooling means
• CPC Class Codes: G06F 2200/201 Cooling arrangements using cooling fluid
• CPC Class Codes: H05K 7/20281 Thermal management, e.g. liquid flow control
• CPC Class Codes: H05K 7/20381 Thermal management, e.g. evaporation control
• CPC Class Codes: Y10S 165/921 Dew point

Abstract

A cooling system for maintaining the temperature within electronic equipment has a circulation system for pumping a cooling liquid, such as water, through the electronic equipment where it picks up heat generated by the electronic equipment. The cooling liquid is pumped through a plurality of heat exchangers using a refrigerant which is, in turn, pumped through a compressor-condensor combination, each heat exchanger having approximately the same cooling capacity. A central control selects the number of heat exchangers which are to operate at any given time, on a basis of the differential in the temperature of the water being pumped into and out of the electronic equipment. This maintains a desired and relatively wide range of temperatures. A heating element selectively and controllably heats the cooled water to bring the wide range of temperatures to a selected and fixed temperature.

Claims

1. A cooling system for controlling the temperature of electronic equipment, said cooling system comprising a circulation system for conveying a cooling liquid into, through and out of said equipment, said cooling liquid being heated by heat of said equipment while it flows through said equipment;

a plurality of heat exchangers for removing heat from said cooling liquid after it leaves said equipment, each of said heat exchangers having a capacity for removing a predetermined amount of heat from said cooling liquid;

control means responsive to a differential of temperatures of the cooling liquids flowing into and out of said equipment for operating a selected number of said heat exchangers which is required to maintain a relatively wide range of temperatures within said equipment;

means in said circulating system for heating the cooling liquid before it enters into said equipment; and

said control means being further responsive to temperature sensing means within said equipment for controlling said heating means to maintain the temperature of the liquid coolant to be fed to said electronic system equal to or higher than the temperature within said electronic system.

2. The system of claim 1 and an expansion tank means containing said heating mleans for accommodating volume changes in said cooling liquid.

3. The system of claim 1 and means wherein said control means selects said heat exchangers for operation in a predetermined cycle whereby each heat exchanger operates for a first period in said cycle and stands by for a second period in said cycle during which at least one other heat exchanger operates.

4. The system of claim 1 wherein said cooling liquid is water and wherein each of said heat exchange units includes a refrigerant pumped through a compressor-condensor combination for removing heat from said water.

5. The system of claim 1 wherein said differential temperature is sensed by temperature sensor means in said system, one of said temperature sensor means measuring the temperature of said cooling liquid before it enters into said equipment, the other of said temperature sensor means measuring the temperature of said cooling liquid after it leaves said equipment, said control means responding to said temperature mesurements from said two temperature sensor means for finding said differential of temperature.

6. The system of claim 5 and an expansion tank means containing said heating means for accommodating volume changes in said cooling liquid.

7. The system of claim 6 wherein said cooling liquid is water and wherein each of said heat exchange units includes a refrigerant pumped through a compressor-condensor combination for removing heat from said water.

8. A cooling system for cooling an electronic system comprising:

supply means for supplying a liquid coolant to said electronic system to take heat from the system;

discharge means for discharging from said electronic system said liquid coolant which has been heated with said heat;

first temperature sensing means for detecting the temperature of said liquid coolant before it is supplied to said supply means;

second temperature sensing means for detecting the temperature of said liquid coolant discharged from said discharge means;

third temperature sensing means for detecting the temperature within said electronic system;

a plurality of heat exchange units for cooling said liquid coolant discharged from said discharge means;

an expansion tank having heating means for heating said liquid coolant supplied from said heat exchange units;

first control means responsive to the difference between the temperature detected by said first temperature sensing means and the temperature detected by said second temperature sensing means for determining the number of said plurality of heat exchange units which is to be operated and for controlling their operations; and

second control means for controlling said heating means in response to the temperature difference between the temperature detected by said first temperature sensing means and the temperature detected by said third temperature sensing means so as to keep the temperature of said liquid coolant to be fed to said electronic system equal to or higher than the temperature within said electronic system.

9. A cooling system as claimed in claim 8, wherein said first control means controls said heat exchange units, so that said determined number of said heat exchange units operate constantly, said first control means periodically rotating the operation of said heat exchange means between said plurality of heat exchange units so that each of said heat exchange units periodically switches between operate and standby conditions.