Sun patents a magneto-hydrodynamic "caterpillar" heatsink

Posted by Rick C. Hodgin

Santa Clara (CA) - Sun Microsystems has been issued a patent for a heatsink design using magneto-hydrodynamic technology in a closed fluid system.  Such a system migrates heat around via the internal liquid, but without mechanical pumping action.  This makes it very quiet and potentially very power and thermally efficient.

Just like the drive system used on the Russian submarine Red October in the movie "The Hunt for Red October," this type of magneto-hydrodynamic, or "caterpillar," is designed to use micro-magnetic fields to squeeze internal bladders which in turn create a pumping action.  While the end result is a real movement of liquid there are no moving parts to this design.  The bladder is squeezed remotely by magnetic fields and is, therefore, almost completely silent.

The purpose of the liquid is to take the heat away from the source and move it up very quickly to its larger surface area which can then expel the heat via metal/air surfaces just like traditional heatsinks.  The interesting part of this design, however, is the use of caterpillar pumping action coupled with a closed liquid system.

We are forced to ask why Sun would patent such a technology?  The answer may lie in their desire to implement larger scale fluid-transfer heatsink systems in servers.  These would cool not only the CPUs, but also chipsets, memory and possibly other peripherials.  The caterpillar system would use less power, be self contained, and could even be hooked up to the traditional motherboard fan connectors for power.  In addition, it could be controlled thermally allowing the pumping action to be turned on/off as needed via software algorithms which monitor the machine's heat state and act accordingly.  Such a system would also be more efficient at utilizing a wider surface airflow by moving the hotter heat spots around to cooler spots in the server, providing a greater degree of cooling in a smaller space.

The patent was filed in September 2005 and awarded in September 2007.  Only one person credited with this invention, Chien Ouyang from Sun Microsystems.