I got a few PCs running in a remote location, and as the # of PCs go up, the temperature is getting out of hand. It's reasonable now, but it seems pretty clear that 15kW isn't ideal when summer is here :p Hence the need to get rid of some heat. Here's a shot of a part of the room:

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Currently there's positive pressure in the room from some air condition unit in the roof, so that air is pushed out through the pipe in the corner. My question is, how much heat can I force through that 12cm diameter opening? The rigs are mostly used for GPU crunching, but there should be about 3000W worth of CPU heat from folding@home running on 18 core xeons as well.

My first thought was to water cool those Xeons (one loop per PC) and use an old water heater as a huge res, and then have a separate loop from the heater to some sort of radiator setup 1-2m in front of the hole, and make an air tight cover (imagine some sort of funnel, with the tip being the hole on the wall) so that the air from the room is forced through the small opening through the rad(s). I do have alot of parts stocked up, including Iwaki pumps, which should be both powerful and of high enough quality.

Thoughts?