That said, you have several options for cooling: natural air, forced air, a combination of both and liquid cooling. People tend to freak out about having liquid cooling in their data center, but if you have a sprinkler system, you already have water in the data center (food for thought). In planning your cooling, you will require one thermal unit of cooling for each KW of power you consume. Here are a few schools of thought to consider:
- Get rid of the abandoned cable under the floor. This is the biggest hurdle to cooling efficiency in many data centers. You can't push air through a wad of cables. By the way, this is also now a code requirement (NEC 2005). An air study will also help. APC has a program to do this (don't worry -- not vendor specific).
- In an natural air flow system, you can increase cooling efficiency by making sure that you have some means to deal with the heated air -- either pull it out of the room, use a very high ceiling to help it dissipate or duct it out of the room.
- With forced air or with a combination of forced and natural air, you assist the cooling by utilizing fans to draw the cool air into the cabinets. A good rule of thumb is to allow two perforated tiles (4') in front of your cabinets. Make sure that any places the cold air can escape (though holes in the floor, blank areas in cabinets, etc.) are stopped with brushes and blanking panels. This improves efficiency.
- Liquid-cooled cabinets provide sort of a personal chilling unit for the enclosed equipment. They are connected to your water pipes and in some cases to a water tank. Many buildings have underutilized chiller units, which can be incorporated into the system.
This was first published in March 2006