[Beowulf] Reasonable upper limit in kW per rack for air cooling?

[David Mathog]

Robert G. Brown wrote:

> In order to for liquid cooling to ever
> make sense for COTS clusters, it would have to BECOME COTS -- basically,
> to become cheap in both hardware and human terms.

Shuttle's itty bitty computers have a heat pipe that goes out to
a radiator on the back of the case.  It isn't much of a step from
there to replacing the back radiator with a copper block.  That block
could in turn mate with another copper block which itself was
on a cold water line.  Ie, move the radiator even further from
the CPU and other heat generating parts of the computer.  So
a company like shuttle could relatively easily start selling
liquid cooled nodes using only minor modifications to its existing
hardware.

In this sort of a system you might have to pay to have the pros 
install (plumb) the rack itself, but you could still work on the
nodes of the rack, as is true now.  It would seem to be relatively
straightforward to have the nodes mate up copper block to copper
block when fully inserted, so that each node is not itself part
of the rack circulation system. The tricky part is
that something else would have to be attached to the copper block
on the back when the node was serviced on the bench.

On the plus side your racks could replace the building's current
hot water supply!

Regards,

David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech