Server closet cooling

I have a room about 10 feet by 40 feet full of shelves with servers. As you can imagine the heat in here is pretty intense, and I find that the central AC that comes in through the ceiling is probably not nearly effective enough. I have a bunch of fans going for circulation, but the tempurature is probably reaching 80 degrees easily.

I'v been looking into portable AC units (no windows in this room, and only one door which has to remain locked). I was hoping for some sort of exuast/drain system that could go out through a hose into the ceiling.

Anyone have good AC units and/or places to buy, or what types of things to look for? Any advice would be much appreciated.

If you can, the air conditioner unit would go on the roof, with the duct serving to bring the cool air into the room. Air conditioners cool outside air and blow it in, they don't suck in interior air to cool. And since they aren't 100% efficient, you don't want the unit in the closed room, since it would generate as much heat as it removed (more really, but you could exhaust some).

I have the exact same issue basically. I have a closet with no windows, a drop ceiling and a few vents for air circulation but the temperature is just too much. I was wondering what your opinion on the Spot Coolers CM12 would be. Since I have a new forum account I can't post links but im sure a google search would be easy enough. They say it can mount in a standard drop ceiling and I was thinking it would just pull air from above the room and blow it down. Let me know what you guys think.

just a suggestion...you may not need additional "cooling" just better ventilation?

have you considered just an exhaust fan? if you can install a fan it would/should remove the heated air (up through the ceiling) and at the same time draw cooler (air conditioned) air in from the adjoining room etc...

i.e., the same way fans are used to cool system cases etc...

you could also look into "split AC"s and "porta-chill"s