The design of the air conditioning system is critical to the efficiency and reliability of the facility as the power requirements for air conditioning alone can be up to a third of the overall power consumption. Increasing attention has to be paid to the efficiency of any data centre cooling system, with local authorities in particular, requesting an energy conservation report to be submitted as part of any planning process. It is therefore imperative that the design is optimised to be as efficient as possible while still supplying the required cooling loads. Various measures can be taken, including :

  • Making use of outside air for cooling when the ambient temperature does not exceed a set level. This saves on running costly air conditioning equipment.
  • Items of equipment more tolerant of running in higher ambient temperatures may be segregated and supplied with vented non air conditioned air, making further savings.
  • Correct setting out of computer racking into a hot and cold aisle configuration will ensure a direct hot air path back to the air handling equipment.

Chilled water systems are normally employed in larger data centres and computer rooms, they have the advantage of being able to run in free cool mode with reduced running costs where conditions allow.

Chilled water systems employ a single set of pipe work to serve any number of computer room air handling units. This reduces the amount of pipe work within the facility but also introduces a single point of failure within the pumps and along the pipe route.

To increase the resiliency of the chilled water system, a second set of stand by pumps are normally employed to allow for maintenance and pump failure.

Further resiliency can be introduced by utilising two sets of pumps and pipe work supplying alternate air handling units through out the facility.