Server Cabinet/Room Cooling

Solution 1:

You're on the right track in terms of ventilating the hot air to the outside. You need to cycle fresh cool air in to the room\cabinet and exhaust the hot air out of the room\cabinet. You do not want to recycle the same air around and around. The key is to maintain airflow through the room: bring fresh, cool air in and send hot air out. My opinion would be to use the exhaust duct in the attic to send the hot air to the outside rather then sending it into the attic. If you have adequate airflow you may not need a portable air conditioner. Try it for a few days\weeks with just exhausting the hot air out of the room and see how that works. If it's still too hot for your comfort level (from the server's perspective) then go ahead and invest in a portable air conditioner. Be wary if the air conditioner has a water collection tank that you'll have to manage the emptying of it unless you can hook up a drain hose to it and sent it down the storm drain\sewer.

Solution 2:

I'd agree with joeqwerty. If you invest in a portable A/C, you want one that's self contained (see my comment above). Additionally, the best way to cool it would be to position the A/C in front of the rack, and not try to cool from bottom to top as you suggested in your question. Cool air is denser than hot air, and even with the vent at the top you risk over-heating with your servers that are higher up in the rack. With the A/C in front of the rack blowing into the intakes of the servers will make sure that they stay adequately cool. To your question about ambient noise, if you're running servers in that room anyways, you won't really notice the additional sound output from the A/C.

Solution 3:

Exhausting the heat to the attic shouldn't prove a problem, assuming you're going to put a fan in the box to drive the hot air. The heat in the attic won't matter: attics have external vents because of the extra heat, and a little more won't even be noticed. Might even cool it off a bit.

I wouldn't get an interior air conditioner for several reasons:

• They're loud
• They're inefficient
• You'll still have to duct the hot air
• You'll also have to run pipe for the condensation

Way more trouble than it's worth.

One problem that is worth thinking about is the effect that venting the heat is going to have on your air conditioning. Keeping the cabinet cool will mean running a lot of air into it, most of which is going straight up to the attic. You can lose a lot more cool air that way than would otherwise be warmed up by the servers. You're probably going to want to experiment with heat exchanging until you find something that's good enough for the servers, and still doesn't suck out all your AC.