Cooling for electronic devices, for example, closely spaced electronic circuit cards with nearly uniform height components, such as dual in-line memory modules (DIMMs), has traditionally been accomplished by circulating air. However, in the electronics industry, more powerful circuits are difficult to cool using air cooling and even for relatively low-power devices air cooling can be inadequate. Alternative cooling methods include using a one piece flat sheet metal heat sink. Although such enhancements to air cooling remove additionally heat, they have proved to be inadequate for providing the additional cooling need for more powerful heat producing electronic devices.
Typically, in order to cool known electronic devices air is blown parallel to a plurality of device, such as a plurality of dynamic random access memory (DRAM) modules 6 on a dual inline memory module (DIMM) 2 as shown in FIG. 1, and DRAMs 6 on DIMM 8 as shown in FIG. 2. It is particularly difficult to cool these devices in any other manner, for example water cooling, because the heat produced by the DRAMs is spread evenly over the several DIMMs and there is limited space between them.
Another shortcoming with prior art devices is the inability to conveniently remove and replace a device that is liquid cooled. Liquid cooling typically requires a thermal interface material (TIM) such as a thermal grease or paste to be applied between the device to be cooled and a heat transfer device such as a cold plate or heat sink. The application of this material must be done in a very controlled manner in order to make good thermal contact between the device to be cooled and the cold plate. The level of control needed is usually beyond what can be done in the field, so an individual liquid cooled device cannot easily be replaced in the field. The alternative to breaking the thermal connection to remove a device is to break a liquid connection such as a hose connection. Connections such as these take up a considerable volume of space. While practical for one or a few devices, having an individual liquid disconnect for many devices uses too much room, making this solution impractical. Any such breakable thermal interface must also be actuated is the same direction as the electrical connectors for the component being cooled.
Additionally, another problem in the art is the space requirements within a computer system for attaching electronic components, for example, DIMMs or small compute cards. An additional problem with known cooling systems is being able to cool multiple types of heat producing electronic components which may be asymmetrically positioned within the computer system. A further problem with current cooling systems is that a lengthy cooling conduit in a cooling system is difficult to form and locate with adequate precision. Where possible, it is desirable to use a single serpentine section of pipe with water cooling to minimize the number of joints needed and simplify the fabrication process.
It would therefore be desirable to provide an apparatus and method for using liquid cooling for removing heat from heat producing electronic devices, which may be angularly juxtapositioned within a computer system. It is further desirable to remove heat from electronic devices where the heat producing devices are a concentrated source of heat, such as a circuit card with memory or compute modules. It would also be desirable to provide a method of liquid cooling a plurality of electronics devices such as several parallel circuit cards each containing several chip packages while allowing the circuit cards to be replaced in the field, and further without disturbing any liquid (e.g., water) connections. There is further need for a method of precisely positioning and retaining a lengthy heat conduit relative to the electrical connectors for the devices.