Cold aisle

Cold Aisle, In-Row & In-Rack – How to Keep Your Server Rack Cool.

Rack Cooling in one form or another is required in all cases where there are server racks with functioning IT equipment.  The importance of rack cooling for all cabinets is often underestimated; however inadequate rack cooling can seriously undermine the performance and longevity of all the equipment in server racks.  Rack cooling is designed to mitigate and even eliminate hotspots in the server racks. The type of rack cooling required in each location depends on the scale of the data centre and reflects the quantity and the location of the servers involved. Rack cooling as a function is defined and described, from the largest scale to the smallest, as ‘Cold Aisle containment’, ‘In-Row’ cooling and ‘In-Rack’ cooling.

Cold Aisle containment refers to the cooling systems used in purpose-built data centres to cool all the equipment in the server racks.  19” racks form the basic structure of datacentres and Cold Aisle containment cooling is achieved by the positioning of the racks to effectively contain and separate the cold and hot air.   Ducting that controls the flow of cold and hot air supports the basic arrangement of server racks.  Usually, plinths and voids are used to create a space where the cold air can be pushed up into the cabinets from underneath.  Cold Aisle containment is a large-scale cooling system that cools the racks in a data centre as a whole.

In-Row cooling describes a situation usually found in small datacentres and server rooms that might provide part of the IT function for a group or business. The room, in this case, might have one or two rows of racks and be unsuitable for structural Cold Aisle containment due to its location within a building or structure. The cooling systems often used in this instance are built into the rows of server racks whereby each rack is separated by a rack of coolers that effectively cools the row of racks. The cold air is pushed across the front of the row and then vented and recycled from the back of each row. In-Rack cooling systems are those that are part of each server rack and precisely cool the contents of each rack.   The server racks are in closed cabinets and the cooling systems internally separate the hot and cold air.  In-Rack cooling is a closed system that is highly effective at eliminating hotspots.  Increasingly, In-Rack cooling has a greater part to play in IT infrastructure as it is extremely useful for high-density server racks often found in edge applications and in micro data centres.   

The agility and flexibility of these small data centres have increased their popularity for office spaces and their effectiveness. In-rack cooling has allowed businesses to develop edge functions. Server rack cooling cabinets are particularly suitable for remote working and processing large volumes of data quickly in house, without latency associated with remote storage. Depending on the scale of the IT function and data storage, either Cold Aisle containment, In-row Cooling or In-rack Cooling is used to keep all the equipment in server racks working as effectively as possible given the variables and limitations of each location.