What is a Hot/Cold Aisle
One of the most difficult tasks associated with running a data center is managing heat. IT equipment and hardware can produce a surprising amount of heat and very quickly. The internal fans on most devices help push heat out into the surrounding environment, but without a proper cooling system, the entire facility can become hot enough to cause serious damage.
All data centers have some type of air cooling system in place. For many facilities, cooling is one of the largest expenses. A cost that does not include expenses associated with having the systems installed and maintained.
How It Works
In its most basic form, a data center will be arranged with all the hardware expelling heat (typically out the back of the units) toward one aisle, where the exhaust vents are placed. The other side of the aisle is designated for cool air.
Avoiding the mixing of warm and cold air helps to improve the efficiency of the entire operation. Many facilities today have taken this a step further and put up barriers between the aisles to stop the mixing of warm and cold air. This could be anything from a simple sheet of plastic, to a wall partition, or even a set of fans.
When this strategy is implemented effectively, it much easier to keep the hardware in the data center at the proper temperature. In addition to making sure the fans on the hardware are all pointed in the right directions, data centers should also have a raised floor. In most cases the raised floor should provide about 1.5 feet of space that can be used to push the air where it needs to be. Under the floor is pressurized, and then floor panels with holes in them (on the cool aisles) will have air coming up to keep things cool.
This type of setup is much easier and more efficient than trying to run duct work to the different areas where cold air is needed. Of course, the raised floors are also great for running cabling to all the different racks in the area.
When possible, the exhaust ducts should pull air out through the ceiling and remove it from the data center as quickly as possible. Unlike the cooling system, you want to keep the hot air exhaust going through ducts, so it is better contained and can be removed as directly as possible.
Setting up a hot aisle/cool aisle system in a data center will certainly take some time and leffort up front, but in the end, it will result in a much more efficient (and cost effective) data center.