What is a cold aisle system?

Cold channel closure (CAC) works by isolating the cold gas supply from the hot exhaust gas and concentrating the cooling on the equipment air intake, a process called centralized cooling. This is achieved by installing IT racks with air intakes facing the cold aisle. This cold aisle is completely surrounded by the ceiling and a door at the end of the aisle, and the cold air is pumped into the equipment intake, and then the air is pushed through the equipment into the exhaust port, which is in the cold aisle outside. This cold channel containment prevents hot and cold air from mixing, which means less energy is needed to keep the system at a controlled and consistent temperature.

You may also have heard of superheated air systems, which work similarly. The hot channel (HAC) encloses the channel through which the hot exhaust gas of the IT equipment is discharged. By isolating hot air, the rest of the data center can circulate cold air freely without worrying about air mixing. While hot air containment systems can save up to 40% of cooling system energy and are more efficient than cold channel containment, these systems are generally not an option for existing data centers. Hot versus cold aisle containment comes down to whether you're building a new data center or partnering with an existing one. In existing centers, the air conditioning and air flow within the data center determines whether hot or cold aisles are best used.