Unlike physical containment systems, virtual containment utilises directional airflow panels which angle airflow toward the face of the rack, nearly eliminating bypass air while increasing cooling capacity and energy efficiency. These panels can achieve a 93% Capture Index – the amount of air delivered through the panel that directly enters the face of the server rack in front of that panel – significantly reducing the amount of bypass air.
Additionally, advances in directional airflow panel design have introduced multi-directional panels where airflow is split evenly and angled in two directions. This allows for delivery of directional airflow to racks on either side of a cold aisle in a legacy data centre that has only one accessible airflow panel. And, for applications where less airflow is required but directionality is needed to more precisely match cooling with heat loads, perforated directional panels are available.
Using a directional panel can save more than 40 percent in fan energy by enabling a rack with equal load to be effectively cooled, using approximately half the CFM of a conventional panel. With less air required and higher Delta Ts, fewer computer room air-handling (CRAH) units may be needed in a new data centre, reducing initial capital expenditures by up to 40 percent. In retrofit applications, CRAH units with fixed-speed fans can be set to standby mode, or variable-fan drives can be adjusted to operate at a lower static pressure, saving energy.