Over the past decade, data center containment has experienced a high rate of implementation by many data centers. It can greatly improve the predictability and efficiency of traditional data center cooling systems. This article will elaborate on what data center containment is, common types of it, and their benefits and challenges.
Data center containment is the separation of cold supply air from the hot exhaust air from IT equipment so as to reduce operating cost, optimize power usage effectiveness, and increase cooling capacity. Containment systems enable uniform and stable supply air temperature to the intake of IT equipment and a warmer, drier return air to cooling infrastructure.
There are mainly two types of data center containment, hot aisle containment and cold aisle containment.
Hot aisle containment encloses warm exhaust air from IT equipment in data center racks and returns it back to cooling infrastructure. The air from the enclosed hot aisle is returned to cooling equipment via a ceiling plenum or duct work, and then the conditioned air enters the data center via raised floor, computer room air conditioning (CRAC) units, or duct work.
Cold aisle containment encloses cold aisles where cold supply air is delivered to cool IT equipment. So the rest of the data center becomes a hot-air return plenum where the temperature can be high. Physical barriers such as solid metal panels, plastic curtains, or glass are used to allow for proper airflow through cold aisles.
There are mixed views on whether it’s better to contain the hot aisle or the cold aisle. Both containment strategies have their own benefits as well as challenges.
The open areas of the data center are cool, so that visitors to the room will not think the IT equipment is not being cooled sufficiently. In addition, it allows for some low density areas to be un-contained if desired.
It is generally considered to be more effective. Any leakages that come from raised floor openings in the larger part of the room go into the cold space.
With hot aisle containment, low-density network racks and stand-alone equipment like storage cabinets can be situated outside the containment system, and they will not get too hot, because they are able to stay in the lower temperature open areas of the data center.
Hot aisle containment typically adjoins the ceiling where fire suppression is installed. With a well-designed space, it will not affect normal operation of a standard grid fire suppression system.
It is generally more expensive. A contained path is needed for air to flow from the hot aisle all the way to cooling units. Often a drop ceiling is used as return air plenum.
High temperatures in the hot aisle can be undesirable for data center technicians. When they need to access IT equipment and infrastructure, a contained hot aisle can be a very uncomfortable place to work. But this problem can be mitigated using temporary local cooling.
It is easy to implement without the need for additional architecture to contain and return exhaust air such as a drop ceiling or air plenum.
Cold aisle containment is less expensive to install as it only requires doors at ends of aisles and baffles or roof over the aisle.
Cold aisle containment is typically easier to retrofit in an existing data center. This is particularly true for data centers that have overhead obstructions such as existing duct work, lighting and power, and network distribution.
When utilizing a cold aisle system, the rest of the data center becomes hot, resulting in high return air temperatures. It also may create operational issues if any non-contained equipment such as low-density storage is installed in the general data center space.
The conditioned air that leaks from the openings under equipment like PDUs and raised floor tend to enter air paths that return to cooling units. This reduces the efficiency of the system.
In many cases, cold aisles have intermediate ceilings over the aisle. This may affect the overall fire protection and lighting design, especially when added to an existing data center.
Every data center is unique. To find the most suitable option, you have to take into account a number of aspects. The first thing is to evaluate your site and calculate the Cooling Capacity Factor (CCF) of the computer room. Then observe the unique layout and architecture of each computer room to discover conditions that make hot aisle or cold aisle containment preferable. With adequate information and careful consideration, you will be able to choose the best containment option for your data center.