As much as 50% of the airflow in a datacentre may be inefficiently distributed, within the room and its server racks. This can lead to higher operating costs, lower energy efficiency and ‘hot-spots’. Cool air can, in effect, bypass some or part of the server racks it is intended to cool and be simply returned to the Computer Room Air Conditioning (CRAC) units. Where this is the case, hot aisle and cold aisle containment systems provide a solution.
There are two forms of containment system available. One for the cold aisle and one for the hot aisle. An installation may use one or both types of containment to prevent hot and cold air paths mixing. The most commonly installed form of containment is a cold-aisle.
Installing an aisle containment system within a server room or datacentre will improve the overall cooling operation and energy efficiency. This in turn can can free-up cooling capacity and reduce the need for additional air-based CRAC units or liquid-based cooling system during unexpected ambient temperature rises, changes in server utilisation or server expansion.
Aisle containment systems provide a number of advantages including:
Cold aisle containment is designed to improve the cooling of server racks and network cabinets. The containment system restricts and routes the flow of cold air, preventing it mixing with the hot air flow within the server room or datacentre. The cold air flow becomes more uniform and predictable and can help to eliminate ‘hot spots’ whilst improving energy efficiency.
A cold aisle containment system can consist of a hard roof and partitions with single or double sliding doors, soft partitions with strip doors and directional airflow panels. The containment system can be configured as needed for the site in terms of the number of server cabinets it is to house.
Cold aisle containment can also help to improve server rack utilisation. The top of most server racks (approximately 15%) is left unpopulated due to hot air recirculation. Placing IT servers within this area can lead to reduced operational reliability. Cold aisle containment eliminates ‘hot-spots’ within racks and cabinets, allowing for fuller population if required.
For server rooms and datacentres, cold aisle containment can lead to improved return on investment (ROI), server rack density improvements, increased revenue per square meter and improved energy efficiency.
Hot aisle containment is designed to guide hot exhaust air flow away from the server room or datacentre working space, to the air conditioning return path. In addition to preventing the hot air from mixing with the cold air flow, the overall room ambient is lowered to create a more comfortable working environment.
Hot aisle containment works on the thermal properties of warm air. The containment directs the rising warm airflow to the air conditioning return via a ceiling void or plenum or duct work. The raised access floor plenum is used to direct cooled air to the IT server racks from the cooling system.
By containing the hot air, the cooling system can become more efficient by up to 30% or more. As the hot air remains relatively dry (low humidity), its temperature can be more more effectively lowered by the cooling system. AC fans also tend to run slower, again helping to improve efficiency and extend their operational lifetimes. The overall effect is a more effective and energy efficient cooling system, with the potential for capacity free for future expansion.
For some server rooms and datacentres standard hot aisle and cold aisle containment systems may be suitable. Where this is not the case, the Server Room Environments projects team can design a bespoke solution. Containment systems are suitable for on-site buildings and containerised facilities. Please contact our projects team for more information.