To add to the advice of "Turn unneeded servers off!" is virtualization. The best way to control heat is to eliminate it. If multiple server can be consolidated into fewer servers, less power is consumed and less heat is produced.
Make sure you've got the hot and cold aisles right with the air flow configured properly. It'll help the servers a lot if you haven't done that.
Without resorting to architectural changes, we've used portable air conditioners in addition to large fans for times when we were doing structural work (like swapping out UPS systems).
Portable air-conditioning units where you just hang a heat-exchanger out of a window work well for a short-term solution until you can get something designed-in.
I was working with a company whose server room was on the first floor in a very well ventilated corner of a building, and they kept complaining about the server room getting too hot despite the air-conditioning.
Turned out that opening the window dropped the temperatures to below 25C for most of the year, and below 20C most of the winter.
Of course there was really good airflow in and out of the room, so I guess it's an exceptional case.
Fans in a closed space are not going to work, as it will just circulate the heat rather than removing it.
Ventalation fans providing fresh air can help when there is a suitable place to pull air in and push air out to.
A small free standing or surface mount air conditioner will work well for small server rooms and comms cabinets, you will need to make sure they are placed in such a position that the air can circulate. They also require somewhere to vent the heat out to.
At the high end:
Get someone in to do a survey and do the calculations for you, it is easy to spend a fortune on something that is either going to be way over the top, or not sufficent.
You can go with a spot type air conditioner such as units like these. These units are self contained and only require a water supply and drain to remove the heat and therefore don't require architectural modification for ducting, etc...only a plumbing hookup. You don't even need to pressure balance the room because the air is completely recirculating. Relative to cost, I believe they are both cheaper to acquire and also more efficient than the more typical air flow based condenser units because the water is better at removing heat from the coils than air.
If you are concerned about the water consumption, for some added cost the water can be recirculated via pipes to an outside radiator to dump off the heat before bringing it back around.
Turn unneeded servers off!
I know it sounds obvious, but I've seen numerous servers left on for no reason, or because people weren't sure they were being used!
To add to the advice of "Turn unneeded servers off!" is virtualization. The best way to control heat is to eliminate it. If multiple server can be consolidated into fewer servers, less power is consumed and less heat is produced.
Make sure you've got the hot and cold aisles right with the air flow configured properly. It'll help the servers a lot if you haven't done that.
Without resorting to architectural changes, we've used portable air conditioners in addition to large fans for times when we were doing structural work (like swapping out UPS systems).
Portable air-conditioning units where you just hang a heat-exchanger out of a window work well for a short-term solution until you can get something designed-in.
My favorite was: open the windows.
I was working with a company whose server room was on the first floor in a very well ventilated corner of a building, and they kept complaining about the server room getting too hot despite the air-conditioning.
Turned out that opening the window dropped the temperatures to below 25C for most of the year, and below 20C most of the winter.
Of course there was really good airflow in and out of the room, so I guess it's an exceptional case.
At the low end:
At the high end:
You can go with a spot type air conditioner such as units like these. These units are self contained and only require a water supply and drain to remove the heat and therefore don't require architectural modification for ducting, etc...only a plumbing hookup. You don't even need to pressure balance the room because the air is completely recirculating. Relative to cost, I believe they are both cheaper to acquire and also more efficient than the more typical air flow based condenser units because the water is better at removing heat from the coils than air.
If you are concerned about the water consumption, for some added cost the water can be recirculated via pipes to an outside radiator to dump off the heat before bringing it back around.