Hot vs Cold Aisle Containment Solutions.
Optimising air flow in your data centre with the use of containment has several key benefits, including reducing energy costs and improving efficiency. Aisle containment solutions separate hot from cold aisles by the use sheet metal walls, raised flooring, suspended ceilings and doors.
Designing and installing hot aisle or cold aisle containment however requires a lot more than just sheet metal knowledge; you will also need to rebalance air flows and air conditioning systems to reap the benefits of containment.
The choice of aisle containment solution is usually decided by the layout of a data centre.
Cold aisle containment is most commonly used where cold air is fed to the server racks using an under-floor plenum (raised floor). Containment is used to keep the cold air to the inlet side of the racks, while the exhaust side is left open allowing the warm air to return to the CRAC units for cooling.
In hot aisle containment the exhaust air is usually sent into a suspended ceiling, returning the warm air to the CRAC units. Since the majority of data centres use raised floors to supply cold air around the room, cold air containment is commonly used in retrofitting, but hot aisle containment is considered where an under-floor plenum doesn’t exist or in new builds. Hot aisle containment systems use ceiling voids or ducting to efficiently return the warm air from the hot aisle to the CRAC’s.
Benefits of Cold Aisle Containment
- Easier to implement; does not require additional architecture to contain exhaust air and return it to the cooling units (suspended ceiling, air plenum etc.).
- Only requires doors at ends and cap at top.
- 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, lighting.
Benefits of Hot Aisle Containment
- Open area of room is a cold environment.
- Leakage from raised floor openings in the larger area of the room goes into the cold space.
- Generally more effective.
- Hot aisle containment will be more forgiving for network racks and stand-alone 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.