Microchannel Cold Plates In Data Centers Cooling

     The application of liquid cooled microchannel heat sinks (liquid cooled plates) in data centers has been proven to be a very effective method for eliminating high heat loads. By reducing the hydraulic diameter of the channel, a larger heat transfer coefficient can be achieved. In parallel structures, small flow rates within microchannels can generate laminar flow, resulting in an inverse ratio of heat transfer coefficient to hydraulic diameter. Reducing the hydraulic diameter will increase the pressure drop, which may lead to unacceptable pumping power.

     By comprehensively considering various processing and manufacturing technologies, changing flow design, and transitioning from linear configurations to three-dimensional complex microchannels, strategies can enhance the heat transfer coefficient and uniformity of microchannel heat sinks.

Reduce space occupation and provide possibilities for high-density computing:

    Liquid cooled plates can significantly reduce the space occupation of heat sinks, providing the possibility of accommodating more computing hardware in high-density enclosures. The size of the traditional server's air-cooled heatsink (length * width * height) is 10 X 10 X 5cm, while the size of the liquid cooled plate (length * width * height) is only 8 X 4 X 0.35cm. The volume of the liquid cooled plate component is 11.2cm3, which is much lower than the 500cm3 of the air-cooled module. The liquid cooled plate not only meets the requirements of high-performance computing units for fast heat transfer, but also saves space for high-density computing integration.

Multiple processing and manufacturing technologies:

     The microchannel structure on the surface of the cold plate bottom plate is a major factor in enhancing heat transfer. At present, the distance between the micro channel teeth of the liquid cooled plate has reached the level of 0.1mm, and its design, processing and manufacturing are one of the core technical challenges of the liquid cooled plate. Multiple methods can be used to manufacture linear microchannels, such as:
1. Skiving process
2. Traditional machining
3. Photochemical Etching (PCE)
4. Electric spark wire cutting
5. Extrusion molding
6. MDT (Micro Deformation Technology)
7. Water jet cutting

Changing fluid direction to enhance heat transfer:

    A parallel flow microchannel cold plate is a heat transfer channel in which liquid flows parallel to the cooled surface. In contrast, Mikros' normal flow ™) Microchannel Cold Plate (NCP) allows liquid to flow through the heat transfer channel in a direction perpendicular to the cooled surface, eliminating the high pressure drop and uneven surface temperature that often occur in common solutions. It can achieve a thermal resistance as low as 0.02 C-cm2/W, with a pressure drop range of 5-35 kPa (1-5 psi).

    At present, the spacing between the micro channels of the liquid cooled plate has reached the level of 0.1mm, and the design and processing need to consider more accurate flow channels and flow resistance, which poses technical barriers and challenges.