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In a reality where cabinet densities are expected to reach 11 kW by 2020 , driving energy efficiency efforts and keeping operating costs down in the data centre has never been so relevant , yet challenging . On one hand , IT equipment within the cabinet must remain operable at all times . On the other , IT managers must ensure that data centre cooling expenses are kept at a minimum . After all , cooling is frequently one of the largest energy consumers in a data centre .
Despite many solutions being introduced in the market , airflow containment – the ability to isolate , redirect and recycle hot exhaust air – has withstood many market trends and stands as the core answer to this juggling act of opposite forces . In fact , the energy savings are so convincing that federal and state governments in the United States are requiring airflow containment in new and retrofit data centre designs . In the United Kingdom , the new ‘ EN 50600 – Data Centre Facilities and Infrastructures ’ was developed and published last year , and a set of best practice guidelines on data centre energy efficiency recommending airflow containment was recently published by the European Commission .
Proven to optimise energy efficiency Many industry associations worldwide have been discussing indirect and direct liquid cooling as possible solutions for highdensity applications . But as a recent white paper describes , perimeter cooling is still a highly efficient solution for today ’ s average rack densities and the anticipated densities over the next decade .
In a complete contained system , it ’ s possible to circulate only the necessary amount of cooled air through the data centre , all while removing the heat actually created by the IT equipment . This eliminates the need to oversupply equipment with cool air , resulting in tremendous energy savings .
Furthermore , by developing and implementing a good airflow containment strategy , it ’ s possible to remove hot spots and achieve a lower Power Usage Effectiveness ( PUE ). Airflow containment and design is also a best practice expected in air-cooled facilities with power densities above 1 kW , according to the aforementioned 2016 EU Code of Conduct on Data Centre Energy Efficiency .
Energy-efficient designs With equipment densities continuing to increase , allowable inlet equipment temperatures will also continue to rise , so implementing airflow containment brings many advantages in energy savings . In deploying an airflow containment strategy , it ’ s important to address some of the cabinet ’ s openings . Within cabinets , unnecessary openings allow pressurised exhaust air to be pushed to equipment intake ports , so these openings should be sealed to create complete hot / cold air separation . Air dams , filler panels , bottom panels , brush grommets and other sealing accessories can deliver best possible isolation .
Once isolation is achieved within the cabinet , the same approach should be taken to the entire room . There are three basic options , each yielding similar performance but different deployment methods , strategies and life cycle costs :
Vertical Exhaust Duct A ‘ chimney ’ at the top of the cabinet guides hot air to the return system . This is a good approach because the interior back of cabinet will be hot , but the room will be cool . Furthermore , deployment is fairly simple because this strategy is centred on the cabinet . There are minimal life cycle costs since there ’ s no need for major room remodels . This is a perfect strategy for new or retrofit installations of high- to mid-density output .
1 . Hot Aisle Containment ( HAC ) This strategy features a barrier that surrounds the ‘ hot ’ aisle and provides a return path for hot air . It includes doors at the ends of adjacent cabinet aisles and an overhead Vertical Exhaust Duct . In this scheme , the room will be cool , and the contained aisle will be hot .
HAC implementation requires a more complex deployment and higher investment cost to implement . The HAC system is adaptable to the site , but must be field-fitted to the row . It must also be deployed on an entire aisle with paired cabinet rows and missing cabinet spaces need to be blocked with full-height panels . The higher cost compared to the Vertical Exhaust Duct strategy is primarily due to the deployment by rows , requirement for doors at the end of rows ( not required with Vertical Exhaust Duct cabinets ) larger duct walls and additional labour to fit the containment system .
2 . Cold Aisle containment ( CAC ) This strategy features a barrier that surrounds the ‘ cold ’ aisle and traps cold air so that it must travel through equipment . This is possible through a ‘ lid ’/ ceiling over the aisle and doors at the ends of adjacent cabinet aisles . In this scheme , the room will be hot and the contained aisle will be cold .
CAC also has complexities during installation . First , it must be deployed by an entire row and requires doors at the end of the rows . In addition , CAC typically requires design changes to the fire suppression system , so higher installations costs are common . One potential issue with CAC is that when used in a high-density application , the volume of the contained space may limit the amount of cold air that can be delivered to equipment in the event of a cooling equipment failure .
Future ready designs Data centres have become the core systems around which businesses operate . Advents such as the Internet of Things ( IoT ), remote medicine and virtual reality , to name a few , are further pushing the thermal envelope .
The type of containment strategy chosen should be based on business requirements and architectural limitations . For as long as there ' s isolation from hot and cold air , any method utilised is valid . But planning seamlessly projects is an added bonus to any successful data centre design . n
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