# US 7,743,820 B2 · Liquid cooling unit with auxillary heat exchanger and auxillary pump

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- Number: US 7,743,820 B2
- Document ID: US7743820B2
- Status: Granted
- Kind: B2
- Application number: 11/270,517
- Filed: 2005-11-10
- Published: 2006-12-28
- Granted: 2010-06-29
- Earliest claimed: 2005-06-24
- Assignees: Fujitsu Limited
- Inventors: Jie Wei
- Web page: https://patentgrep.com/patent/US7743820B2

## CPC

- H05K 7/20281: {Thermal management, e.g. liquid flow control}
- G06F 1/20: Cooling means
- G06F 2200/201: Cooling arrangements using cooling fluid
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

The circulation main loop supplies the liquid coolant by means of the main pump to the cooling plate which cools the electronic element, and then, dissipates the heat by the main heat exchanger 20 to return the same to the reservoir tank. The circulation sub-loop supplies the liquid coolant by means of the sub-pump, and after dissipating the heat by the sub-heat exchanger, returns the same to the refrigerant tank. The controller controls as required the supply flow rate from the main pump and the sub-pump.

## Claims

### Claim 1

A liquid cooling unit for an electronic device, comprising:
a circulation/heat-dissipation main loop including:
a reservoir tank storing a liquid coolant;
a cooling plate provided on electric elements, and absorbs heat from the electric elements;
a main pump circulating the liquid coolant of said reservoir tank into the cooling plate; and
a main heat exchanger dissipating heat from the liquid coolant released from said cooling plate, and then returns the same to said reservoir tank;
a circulation/dissipation sub-loop including:
the reservoir tank;
an auxiliary heat exchanger; and
a sub-pump supplying the liquid coolant of said reservoir tank directly into the auxiliary heat exchanger, the auxiliary heat exchanger further dissipating heat from the liquid coolant and the returning the same to said reservoir tank,
a controller configured to increase a flow rate of the sub-pump when the temperature of the liquid coolant in the reservoir tank exceeds a threshold temperature.

### Claim 2 (depends on 1)

The liquid cooling unit according to claim 1, wherein the controller increases the flow rate of the sub-pump when the temperature of the liquid coolant in the resevoir tank exceeds the threshhold temperature.

### Claim 3 (depends on 1)

The liquid cooling unit according to claim 1, wherein the controller decreases the flow rate of the sub-pump when the temperature of the liquid coolant in the reservoir tank falls below the threshold temperature.