Tate has published a white paper that identifies server leakage as a large potential source of bypass air in contained cold aisles. Tate conducted a study of 10 servers from five leading manufacturers and found the servers will leak cold air into the hot aisle at a rate of 23 to 135 percent of their designed flow rate, when a positive static pressure is experienced at the server inlet. Leakage at these rates will significantly impact annual energy costs to operate data centers.
In response to these findings, Tate is expanding its product offering for the data center market with SmartAire P, a pressure sensing, automatic variable-air-volume damper that minimizes bypass airflow through servers, racks and other containment structures.
Constant airflow into a contained system with a variable-load profile wastes energy during times of nonpeak load performance as airflow is forced through servers and other spaces in the containment structure. The Tate study indicates as much as 300 to 600 cfm of bypass airflow can be forced through a 42U rack of servers in idle mode. By installing SmartAire P under a portion of the airflow panels in the cold aisle, airflow can be automatically varied to maintain a desired static pressure.
When servers enter an idle state, they draw less air from the contained system, causing static pressure in the aisle to increase. As the static pressure increases, more air is forced through the servers, even when fan speeds are reduced. The SmartAire P is daisy chained to SmartAire C units for a primary/secondary configuration that automatically modulates all dampers in the aisle to control the static pressure and maintain a user defined set point. The resulting balance eliminates leakage through idle servers and other gaps in the containment structure.