As rack densities inevitably climb, the challenges above become more severe. The infrastructure struggles to deliver a sufficient volume of cool air to the equipment and to move exhaust air to the air handlers. As it's forced to deliver colder air at a greater CFM, the cooling scheme consumes more energy from the fans through the pumps, down to the chiller. And even under minimal loads, the efficiency of these systems is suspect. The premise of cold aisle containment, though simple, can improve cooling performance.
The Evolution of Cold Aisle Containment
Cold Aisle Containment started as a makeshift design using the vinyl curtains common in clean rooms and freezers. These curtains, functioning as doors and roofs between the cold aisles, proved an inexpensive way to increase efficiency and a simple, flexible retrofit for most data center environments.
As more data centers embrace the concept, some rack manufacturers are bringing their own cold aisle containment systems to market. The barriers, instead of curtains, are fabricated from steel and use polycarbonate inserts to provide a viewing window into the cold aisle.
The same rack manufacturers, in new construction or renovation projects, may promote the use of containment with In-Row air conditioners. These units, more compact, are embedded within the row of server racks, immediately capturing server exhaust air, conditioning it, and distributing it to the cold aisle.