Today I talked to a facilities engineer for a lab data center. They have already added strip curtain doors to the ends of the cold aisles and the top of the aisle remains uncapped. Next, they plan to install VFDs and put temperature sensors at the rack tops in the cold aisle. They plan to drive the VFD’s off the temperature at the top of the cold aisle.

This is an interesting approach because it seems to assure that the air flow is sufficient to the cold zone. And, with an open top, it is especially important to assure sufficient cold air into the aisle. Without that, or in an under-supply situation, the aisle would take hot exhaust air from over the tops of the racks.