BRIEF DESCRIPTION OF THE DRAWINGS
Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
FIG. 1 is a perspective view of a compact liquid cooling unit having a heat exchanger extending diagonally across the housing according to the present invention;
FIG. 2 is a top view of the compact liquid cooling unit illustrated in FIG. 1 without the housing top;
FIG. 3 is a top view of the compact liquid cooling unit illustrated in FIG. 2 with cooling fins spaced non-uniformly apart;
FIG. 4 is a top view of the compact liquid cooling unit illustrated in FIG. 2 with cooling fins positioned parallel with the housing axis;
FIG. 5 is a top view of the compact liquid cooling unit illustrated in FIG. 2 with cooling tubes bowed between an inlet header and an outlet header with cooling fins positioned perpendicular with the housing axis;
FIG. 6 is a top view of the compact liquid cooling unit illustrated in FIG. 2 with a compensator;
FIG. 7 is a perspective view of an alternative embodiment of a compact liquid cooling unit with a heat exchanger extending diagonally upwards from the housing bottom to the housing top and with headers disposed along the top and bottom of the housing, respectively; and
FIG. 8 is perspective view of an alternative embodiment of a compact liquid cooling unit with a heat exchanger extending diagonally upwards from the housing bottom to the housing top as shown in FIG. 7, but along the sides of the housing.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a liquid cooling unit 20 is generally shown for dissipating heat generated by an electronic device (not shown).
The cooling unit 20 comprises a housing 22 generally indicated having a box-like periphery. The housing 22 has a bottom 24 and a top 26 with each having four corners 28. Opposing sides 30 extend between the bottom 24 and the top 26 along a housing 22 axis (AH) between an open entrance end 34 and an open exit end 36. The housing 22 defines an access opening centered at the bottom 24. Although FIGS. 1-8 show the access opening centered at the bottom 24, the opening may be located elsewhere.
The cooling unit 20 further includes a mounting frame 38 and a cold-plate 40. The mounting frame 38 defines a cold-plate 40 opening and is mounted to the bottom 24 about the access opening. The cold-plate 40 is mounted to the frame and overlays the cold-plate 40 opening. The cold-plate 40 normally overlies the electronic device for conducting heat. The cold-plate 40 has a plate inlet 42 and a plate outlet 44 for providing a path such that liquid can flow through the cold-plate 40. As liquid flows through the cold-plate 40, heat generated by the electronic device is transferred to the liquid.
A heat exchanger 46 generally indicated is used to extract heat from the liquid, as discussed further below. The heat exchanger 46 includes a heat exchanger 46 axis (AHEX), an inlet header 50, an outlet header 52, and a plurality of cooling tubes 54. The inlet header 50 and the outlet header 52 have an inlet spout 56 and an outlet spout 58, respectively, for delivering liquid to and from the headers 50, 52. A plurality of cooling tubes 54 are spaced from each other and extend between the headers 50, 52. An air moving device 60 (not shown) is normally used to increase airflow through the heat exchanger 46.
A plurality of cooling fins 62 is disposed between adjacent cooling tubes 54 to define air passages 67. Traditionally, cooling fins 62 have been disposed perpendicular to the heat exchanger 46 axis (AHEX) as illustrated in FIG. 2. However, the cooling fins 62 can be disposed in various positions to optimize airflow through the air passages 67. For example, FIG. 3 shows the cooling fins 62 disposed perpendicular to the heat exchanger 46 axis (AHEX) and spaced from each other at a non-uniform distance. The distance increases as the cooling fins 62 traverse from the inlet header 50 to the outlet header 52, i.e., in the direction of air flow from or along the air flow path. The non-uniform spacing increases the heat transfer surface in areas where more air pressure is available such that overall heat transfer is increased. Preferably, the cooling fins 62 are orientated parallel with the heat exchanger 46 axis (AHEX) as illustrated in FIG. 4. By orientating the cooling fins 62 parallel with the heat exchanger 46 axis (AHEX) the cooling fins 62 are aligned with air flowing through the housing 22 and non-productive air pressure drop can be reduced. Additionally, the longer fins increase overall surface area such that heat transfer may be increased. Alternatively, the cooling tubes 54 can be bowed between the headers 50, 52 as illustrated in FIG. 5. By bowing the heat exchanger 46, air flow uniformity can be increased. The surface area of heat exchanger 46 is also increased for increasing heat transfer. The cooling fins 62 can be disposed in positions including, but not limited to, those described above.
A pump 64 having a pump inlet 66 and a pump outlet 68 is used for pumping liquid. A pump hose 70 interconnects the pump outlet 68 to the inlet spout 56 for delivering liquid from the pump 64 to the inlet header 50. A cooling hose 72 interconnects the outlet spout 58 and the plate inlet 42 for delivering liquid from the outlet header 52 to the cold-plate 40. A return hose 74 interconnects the plate outlet 44 and the pump inlet 66 for delivering liquid to the pump 64.
A compensator 76 can be disposed within the pump 64 for maintaining liquid volume and pressure in the hoses 70, 72, 74, 78 as illustrated in FIGS. 1-5 and FIGS. 7-8. Alternatively, the compensator 76 can be disposed externally from pump 64 as illustrated in FIG. 1 and FIG. 6. The compensator 76 includes a compensator inlet 80 and a compensator outlet 82. Accordingly, a compensator hose 78 interconnects the outlet spout 58 and the compensator inlet 80 for delivering liquid from the outlet header 52 to the compensator 76. The cooling hose 72 interconnects the compensator outlet 82 to the plate inlet 42 for delivering liquid from the compensator 76 to the cold-plate 40. Although hoses 70, 72, 74, 78 are illustrated in the Figures, other conduits may be used.
The liquid cooling unit 20 is distinguished by the heat exchanger 46 axis (AHEX) extending diagonally across the housing 22 and at an acute angle to the housing 22 axis (AH) The heat exchanger 46 axis (AHEX) defines a wedge-shaped entrance air plenum 84 adjacent the open entrance end 34 of the housing 22 and a wedge-shaped exit air plenum 86 adjacent the open exit end 36 of the housing 22. The headers 50, 52 are sealed to the housing 22 for directing air through the air passages 67 and across the cooling tubes 54. Additionally, the pump 64 is disposed on the bottom 24 in the wedge-shaped entrance air plenum 84.
FIGS. 1-5 illustrate a first embodiment having the inlet header 50 disposed vertically between the top 26 and the bottom 24 at one of the corners 28 adjacent one side at the open entrance end 34. The outlet header 52 is disposed vertically between the top 26 and the bottom 24 at another of the corners 28 adjacent the opposite side at the open exit end 36. Accordingly, the heat exchanger 46 extends diagonally across the bottom 24 of the housing 22 and the return hose 74 and the pump hose 70 define one half loop of a closed circuit. The cooling hose 72 defines one other half of the closed circuit with the half loops forming oppositely facing C shapes as viewed from above. When the compensator 76 is disposed externally from the pump 64 as illustrated in FIG. 6, the return hose and the pump hose 70 define one half loop of a closed circuit. The cooling hose 72 and the compensator hose 78 define one other half of the closed circuit with the half loops forming oppositely facing C shapes as viewed from the top 26.
In a second embodiment illustrated in FIG. 7, the inlet header 50 is disposed at the bottom 24 adjacent to the open entrance end 34. The outlet header 52 is disposed at the top 26 adjacent the open exit end 36. The cooling tubes 54 extend between the headers 50, 52 and parallel to the heat exchanger 46 axis (AHEX). Accordingly, the heat exchanger 46 extends diagonally upward from the bottom 24 adjacent to the open entrance end 34 to the top 26 adjacent to the open exit end 36.
In a third embodiment illustrated in FIG. 8, the inlet header 50 is disposed horizontally between the top 26 and the bottom 24 at one of the corners 28 adjacent one side. The outlet header 52 is disposed opposite from the inlet header 50 horizontally between the top 26 and the bottom 24 at another of the corners 28. The headers 50, 52 extend from the bottom 24 adjacent the open entrance end 34 to the top 26 adjacent the open exit end 36 and parallel with the opposite sides. The cooling tubes 54 extend between the headers 50, 52 and perpendicular to the heat exchanger 46 axis (AHEX). Accordingly, the heat exchanger 46 extends diagonally upward across the housing 22 from the bottom 24 to the top 26.
The cooling unit 20 is highly responsive to the instantaneous thermal load imposed on the cold-plate 40 generated by the electronic device. More specifically, the thermal load increases as liquid is heated by the electronic device through the cold-plate 40. The heated liquid is directed to the heat exchanger 46. As the heated liquid flows within the cooling tubes 54, air flows across the diagonally disposed heat exchanger 46 and through the air passage 67. The airflow removes the heat from the liquid and the heated air is exited from the housing 22. The cooled liquid is returned to the pump 64 for re-circulation.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The invention may be practiced otherwise than as specifically described within the scope of the appended claims.
Patent Application
20070272397
