Patent Publication Number: US-2007107441-A1

Title: Heat-dissipating unit and related liquid cooling module

Description:
TECHNICAL FIELD  
      The present invention relates to cooling modules and, more particularly, to a heat-dissipating unit and a liquid cooling module having the same.  
     BACKGROUND  
      Conventional information processing apparatuses, such as personal computers, employ an air-cooling method to air-cool heat producing elements like CPUs (central processing units). In this method, a plurality of heat radiating fins is attached to the heat producing element, and a cooling fan is attached to a top of the radiating fins directing a flow of cool air whereby cooling is achieved by air circulation.  
      As operating speeds of the CPUs and other electronic elements used in the information processing apparatus has been steadily increased (in recent years, power consumption of the CPU has been close to 100 W) conventional air-cooling methods have become insufficiently cooling to be able to deal with the increased heat output of CPUs.  
      As a technique for cooling the CPU with increased power consumption, liquid cooling is mainly used for personal (i.e. desktop) computers. A liquid cooling module using the liquid cooling technique includes a cooling jacket, a radiator and a pipe being connected therebetween. A cooling liquid circulates in a passage of the cooling module. The cooling jacket is attached to the CPU to allow the cooling liquid to absorb heat generated by the CPU. Then, the cooling liquid flows to the radiator, and the radiator radiates the excess heat. The liquid cooling technique is more efficient at transferring heat of CPU than the air-cooling method.  
      However, the conventional liquid cooling module usually is bulky, and cannot be disposed in a computer enclosure easily. Usually, the liquid cooling module is disposed out of the computer enclosure, thus occupying a lot of space, and making the assembly difficult to move.  
      What is needed, therefore, is a compact liquid cooling module which can be fitted inside the enclosure.  
     SUMMARY  
      In accordance with an embodiment, a liquid cooling module includes a heat-absorbing unit, a heat-dissipating unit, a outlet pipe and a inlet pipe. The heat-dissipating unit includes a tank configured for receiving a coolant therein, a pump disposed in the tank, at least one thermoelectric device and at least one heat sink. The thermoelectric device has a first surface and a second surface facing away from the first surface, the first surface thereof is attached to the tank. The heat sink is attached to the second surface of the thermoelectric device. The outlet pipe interconnects the heat-absorbing unit and the pump. The inlet pipe interconnects the tank and the heat-absorbing unit.  
      Other advantages and novel features will become more apparent from the following detailed description of present liquid cooling module, when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Many aspects of the present liquid cooling module can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present liquid cooling module. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.  
       FIG. 1  is a perspective, cut-away view of a liquid cooling module according to a first embodiment;  
       FIG. 2  is a schematic, perspective view of a liquid cooling module according to a second embodiment; and  
       FIG. 3  is a cross-sectional view taken along line III-III of  FIG. 2 . 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
      Embodiments of the present liquid cooling module will now be described in detail below and with reference to the drawings.  
      Referring to  FIG. 1 , a liquid cooling module  1  according to a first embodiment includes a heat-absorbing unit  10 , a heat-dissipating unit  20 , connecting pipes  30  connecting the heat-absorbing unit  10  and heat-dissipating unit  20 , and a coolant circulating between in the heat-absorbing unit  10 , the heat-dissipating unit  20  and the connecting pipe  30 .  
      The heat-absorbing unit  10  is generally attached to a heat-generating component  40  for absorbing heat from the heat-generating component  40 . The coolant takes the heat from the heat-absorbing unit  10  to the heat-dissipating unit  20 .  
      In the first embodiment, the heat-dissipating unit  20  includes a tank  21 , a pump  25  disposed in the tank  21 , two thermoelectric devices  22 ,  22 ′and two heat sinks  23 ,  23 ′. The tank  21  is configured for receiving a coolant therein. The thermoelectric device  22  has a first surface  221  and a second surface  222  facing away from the first surface  221 . The first surface  221  is relatively cool and the second surface  222  is relatively hot in use, and the first surface  221  is attached to the tank  21 . The thermoelectric device  22 ′ is similarly to the thermoelectric device  22 , and has a first surface  221 ′ and a second surface  222 ′ facing away from the first surface  221 ′. The two heat sinks  23 ,  23 ′ are respectively attached to the second surfaces  222 ,  222 ′ of the thermoelectric devices  22 ,  22 ′. The two thermoelectric devices  22 ,  22 ′ are disposed at a same side of the tank  21 . In order to decrease heat resistance between the tank  21  and the two thermoelectric devices  22 ,  22 ′, two thermal interface materials  27 ,  27 ′ are respectively disposed between the tank  21  and the two thermoelectric devices  22 ,  22 ′.  
      In order to decrease heat resistance between the two thermoelectric devices  22 ,  22 ′ and the two heat sinks  23 ,  23 ′, two thermal interface materials  28 ,  28 ′ are respectively disposed therebetween. In order to improve a heat dissipating efficiency of the heat sinks  23 ,  23 ′, two fans  24 ,  24 ′ are respectively attached to the heat sinks  23 ,  23 ′.  
      The connecting pipes  30  includes an inlet pipe  31  and an outlet pipe  32 . The inlet pipe  31  interconnects the heat-absorbing unit  10  and the pump  25 , and the outlet pipe  32  interconnects the heat-absorbing unit  10  and the tank  21 .  
      The coolant is selected from the group consisting of water, ammonia, carbinol, acetone, heptane, and any suitable combination thereof. The coolant is preferably a suspension having thermally conductive particles.  
      The heat-dissipating unit  20  further includes a coolant level meter  26  in communication with the tank  21 . The coolant level meter  26  has a coolant level observing window  261  and a coolant inlet  262 . From the observing window  261 , an observer can see the coolant level in the coolant level meter  26  and know the coolant level in the tank  21 . If the coolant level in the tank  21  is lower than the acceptable coolant level of the pump  25 , coolant can be injected into the tank through the coolant inlet  262 . In the first embodiment, the coolant level meter  26  is disposed between the two heat sinks  23 ,  23 ′, the observing window  261  is a transom window of the coolant level meter  26  formed by using transparent material as a top of the coolant level meter  26 , and the coolant inlet  262  is located on a wall of the coolant level meter  26  away from the tank  21 .  
      In operation, the heat-generating component  40  generates heat. The heat-absorbing unit  10  absorbs heat from the heat-generating component  40 . The heat-generating component  40  can be an electronic component such as a CPU or an IC (integrated circuit) package. The heat absorbed by heat-absorbing unit  10  is transferred to the heat-dissipating unit  20  to be dissipated by the circulation of the coolant. The coolant conveys the heat in the heat-absorbing unit  10  and discharges the heat to the tank  21 . The heat absorbed by the tank  21  is transferred to the heat sinks  23 ,  23 ′ through the two thermoelectric devices  22 ,  22 ′, respectively, and is then dissipated to the environment. Thereby, the heat-generating component  40  can operate at an optimum temperature.  
      During the heat-dissipating process of the liquid cooling module  1 , the first surfaces  221 ,  221 ′ of the thermoelectric devices  22 ,  22 ′ are relatively cooler than the environment, thereby improving the thermal conduction efficiency between the tank  21  and the first outer surfaces  221 ,  221 ′. The second surfaces  222 ,  222 ′ of the thermoelectric devices  22 ,  22 ′ are relatively hotter than the environment, thereby improving the thermal conduction efficiency between the heat sinks  23 ,  23 ′ and the second outer surfaces  222 ,  222 ′.  
      Furthermore, as the pump  25  is disposed in the tank  21 , the thermoelectric devices  22 ,  22 ′ are in contact with the tank  21 , and the heat sinks  23 ,  23 ′ are in contact with the thermoelectric devices  22 ,  22 ′, the volume of the heat-dissipating unit  20  is reduced compared to conventional devices. Thereby, the heat-dissipating unit  20  can be disposed in a storage bracket of the computer enclosure. Accordingly, the liquid cooling module I can be easily disposed inside the computer enclosure.  
      Referring to  FIGS. 2 and 3 , in the second embodiment, the liquid cooling module  1 ′ is similar to the liquid cooling module  1 . The difference is that the heat-dissipating unit  20 ′ further includes a casing  29 . The casing  29  has a plurality of heat-dissipating holes  291  defined therein spatially corresponding to heat sinks  23 ,  23 ′. The casing  29  also has a hole  292  aligned with the coolant inlet  262  of the coolant level meter  26 .  
      The casing  29  is used for protecting the heat-dissipating unit  20 ′, and the heat-dissipating unit  20 ′ protected by the casing  29  can be disposed easily and securely.  
      It is understood that the above-described embodiments are intended to illustrate rather than limit the invention. Variations may be made to the embodiments and methods without departing from the spirit of the invention. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.