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Re: rack power question, and a prediction about "direct heat removal" (DHR)

  • From: Marshall Eubanks
  • Date: Fri Apr 04 09:03:27 2008



On Apr 4, 2008, at 5:14 AM, <[email protected]> wrote:

My guess is that someone will come up with an inexpensive,
reliable way to put a heat collector, which will basically
look like a car radiator the size of a rear rack door,
directly behind the hot air coming from the systems in the rack.

b) air is a lousy way to transfer heat away
from where you want it to be compared to other materials.

So how did you propose to get the heat from the equipment to the car-radiator door?

The idea of making the entire room into a refrigerator by
bringing coolant to the racks is a good one, but I think
that for this to be successful, more attention needs to be
paid to physical placement of things, and the chillers need
to be broken open. By that I mean that chillers cease to be
a big box at the edge of the room because they are now part
of the room itself. Think of a flat chiller attached to the
ceiling with spaces for racks to be inserted into it.


Dealing with heat transport is an important part of the design of spaceflight hardware, with no
convenient gases to extract heat in most cases. Heat pipes, which can have thermal conductivities much
higher than solid copper, are commonly used to transport heat to
outside radiators, but more important is that the entire system is engineered to remove the heat of operation from where it is created to where it can be radiated away.


It sounds to me that blade systems are reaching the point where heat transport will also have to be designed into the rack system, and maybe also into the room system. A set of heat pipes could, for example, remove heat from blades and bring it to the floor of the rack, say to a radiator directly into the plenum of the airflow.

The working fluid inside heat pipes is unlikely to leak, and typically contains very little fluid, but in any case could be chosen to be something that would be fairly benign if the pipe was breached, say methanol.

There might be a business model here...

Regards
Marshall


--Michael Dillon