September • 2015
For companies with large data centers, getting the maximum efficiency from the computer systems that manage and store the data is critical. There is much more to maintaining an optimal data center environment than simply piling all of the equipment in a room and turning it on; proper air flow in, out and around the machinery is critical to performance.
Two types of air flow need to be managed in a data center: cool air that flows into the IT equipment and the hot air that exits from the exhaust systems of the equipment. For maximum efficiency of the machinery, “mixing” of the hot and cold air should be avoided as much as possible. Another requirement for maximum efficiency is that the hot return air temperature should be as high as possible.
Separating Air Flow
There are several ways to configure a data center to promote the separation of the cool intake air and hot exhaust air. The best method for a company will depend on the shape and size of the data center, whether it is being constructed new or remodeled from existing space and the number and type of servers in the center. In many cases, a data center will incorporate more than one strategy to prevent mixing.
1. Hot and Cold Aisles - In this configuration, the racks that hold the servers are lined up in rows so that all of their exhaust ports face in the same direction, away from the cool air intake areas. The resulting “cool aisles” are fed with cooler air that, ideally, does not mix with the “hot aisles”.
2. Physical separation - This method involves constructing dividing walls to completely separate the cool front of each computer server from the hot exhaust in the back. Various types of temporary dividers such as plastic curtains specifically made for this purpose can be installed to keep the hot air from mixing with the cold. Dividers should also be utilized to prevent hot or cold air from seeping over the top or under the bottom of the racks that hold the IT servers.
3. Air handlers - The climate control system for a data center needs to be very different than one for ordinary office space. Climate control for personnel work areas is designed to provide a consistent, pleasant temperature throughout the entire space. In comparison, a data center needs to have different temperatures in different parts of the room to keep the computer equipment cool and the hot exhaust properly vented. This means that air diffusers should be positioned to provide cold air directly to the equipment; consistent temperatures and reduction of drafts is not important, and can even hurt efficiency.
4. Leak Prevention - No matter what type of configuration you use to prevent mixing, it is important to look for any places where inadvertent mixing could occur. For example, review the places where electrical cords exit each server to insure that hot air is not leaking out of the space. Make sure that ceiling space (which usually houses the hot return air duct work) is big enough to handle the large flow of air through them without backing up, which could cause leakage into the cooler parts of the room.