Adaptive cooling method for computer rack enclosure

Abstract

A technique for cooling equipment racks that contain multiple individual devices, such as computers, that each have their own internal cooling fans. An air passage ('shunt tube') is placed between a compartment inside the rack, and the ambient air outside the rack, or between compartments inside the rack. Sensors inside the air passage detect movement of the air inside the passage, and thus indirectly measure the presence of a differential pressure. The preferred sensor embodiment uses temperature sensors, and takes advantage of the differences of the air temperatures inside the computer rack, and outside the computer rack (or between internal computer rack compartments) to determine if the air is moving through the air passage, and which direction the air is moving. In response to the measurements, a control system is configured to drive the plenum to a slight vacuum, and then slowly reduce an exhaust fan until the plenum is slightly pressurized, at which point the fan speeds up and again creates a slight vacuum. This allows the rack enclosure to continuously adapt to any changes in cooling requirements, as the computer utilization changes.