At 3:17 PM +0000 3/29/08, Paul Vixie wrote:
page 10 and 11 of <http://www.panduit.com/products/brochures/105309.pdf> says there's a way to move 20kW of heat away from a rack if your normal CRAC is moving 10kW (it depends on that basic air flow), permitting six blade servers in a rack. panduit licensed this tech from IBM a couple of years ago. i am intrigued by the possible drop in total energy cost per delivered kW, though in practice most datacenters can't get enough utility and backup power to run at this density.
While the chilled water door will provide higher equipment density per rack, it relies on water piping back to a "Cooling Distribution Unit" (CDU) which is in the corner sitting by your CRAC/CRAH units. Whether this is actually more efficient depends quite a bit on the (omitted) specifications for that unit... I know that it would have to be quite a bit before many folks would: 1) introduce another cooling system (with all the necessary redundancy), and 2) put pressurized water in the immediate vicinity of any computer equipment. /John