Mitsubishi claims electronics cooling breakthrough

JAPAN: Mitsubishi Electric has developed what it claims is the world’s first technology to generate mm-scale flow within a channel, potentially eliminating the need for external pumps.

Developed through joint research with Suzuki & Namura Laboratory at Faculty of Engineering and Graduate School of Engineering, Kyoto University, this technology uses microbubbles with a diameter of 10μm as the driving source. The technology is expected to reduce power-consuming external pumps for water cooling in electronic equipment.

With the growth of AI servers, demand is expanding for cooling systems that circulate liquid through microchannels to achieve greater efficiency than conventional water cooling systems.

To further improve the efficiency of microchannel cooling, efforts are being made to reduce the microchannel width to 100μm or less. However, a powerful external pump is required to circulate liquid in microchannels, so the increasing power consumption of these systems has become an issue.

Kyoto University developed a technology generated by local heating and Marangoni forces arising from temperature differences at vapour-liquid interfaces and self-oscillation to induce flow. 

Mitsubishi Electric researched methods to apply this technology to a microchannel and succeeded in generating a world-first flow speed of 100μm/s in a 3mm x 3mm square channel with a cross section of 100µm x 400µm, all without using external pumps. Later, the flow speed was improved to 440μm/s by optimising the bubble layout and flow-path geometry.