17 additional architecture to contain exhaust air and return it to the cooling units ( drop ceiling and air plenum etc .)
AISLE CONTAINMENT
17 additional architecture to contain exhaust air and return it to the cooling units ( drop ceiling and air plenum etc .)
• Only requires doors at ends of aisles and baffles or roof over the aisle
• Generally , less expensive
• Cold aisle containment is typically going to be easier to retrofit in an existing data centre , particularly when there are overhead obstructions to circumnavigate , such as power and network distribution , ducts and lighting .
• Cold aisle containment doesn ’ t absolutely need to be on a raised floor , but it typically is because of challenges associated with delivering supply air to the contained space ( s ).
Assuming a computer room is configured in such a way that either is viable , hot aisle containment may be seen as the better option because it has some working environment and ride-through advantages . However , because every computer room is unique , there ’ s no one definitive solution . For this reason , it ’ s important to understand all the differences between hot aisle containment and cold aisle containment so you can make a decision appropriate to a particular architectural environment and business strategy . For clarification , cold aisle containment involves doors on the ends of the cold aisles and some form of partitions , baffles , or roof over the cold aisle . Hot aisle containment includes doors on the ends of the hot aisle and a configuration of baffles or ductwork from the hot aisle to the returns of the cooling units . Drop ceiling plenums are often used as the means to duct the return air back to the cooling units . Both strategies have their benefits as well as their challenges :
Cold aisle containment benefits :
• Often easier to implement as it doesn ’ t require
Cold aisle containment challenges :
• In cold aisle containment , the overall data centre becomes the hot aisle . All areas not in the cold aisle are part of the hot aisle . If cold aisle containment is done well the rest of the space could be dramatically hot if the theoretical advantages of containment are fully pursued , i . e . higher supply temperatures and reduction of bypass airflow resulting in very high return air temperatures .
• There may not be any space with a suitable temperature profile for equipment that for whatever reason isn ’ t compatible with living in the cold aisle arrangement . This could mean lowering the supply temperature and / or allowing more bypass airflow to accommodate the equipment that doesn ’ t fit in the cold aisle . This would result in losing some of the economic benefits of full separation .
• Any leakage from the raised floor plenum not in the contained cold aisle , such as from under PDUs , enters the hot area and mixes with the return air , thus lowering the return air temperature . This reduces the efficiency of the system .
• Full cold aisle containment creates what the NFPA codes call a ‘ separate volume ’, so there needs to be fire suppression for the overall data centre space and then either additional fire suppression for the contained cold aisle or the containment must be connected to the smoke detection system and remove itself as an obstruction on a smoke alarm .
Hot aisle containment benefits :
• The open , larger area of the room , is a cold environment .
• Leakage from raised floor openings in the larger area of the room goes into the cold space .
• Generally easier to implement to maximum efficiency .
• Hot aisle containment will be more forgiving for network racks and standalone equipment such as storage cabinets that might have to live outside the containment architecture , i . e . they will live in the lower temperature area of the computer room .
• Hot aisle containment can perform well in a slab environment by merely flooding the data centre with an adequate volume of supply air and containing the exhaust air .
• Enables more surface area for cold sinks , with or without a raised floor , for ride through in the event of power failure and engine generators not starting .
• Hot aisle containment , by virtue of the containment
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