Project: Hot-Aisle Containment

Project: Hot-Aisle Containment


A Nashville retailer, with over 180 stores nation-wide, has recently undergone several major data center renovations to grow their data center capabilities. Their biggest challenge is that they need to grow without expanding the physical size of the data center, which is currently at maximum capacity.

This land lock results in the choice to increase the power density of their existing racks. However, once they begin to raise the power capacity of each rack in the data center, it becomes increasingly difficult to cool the same amount of space than before. They need an InfraStrategy that could handle this power increase while consuming the least amount of floor space possible to handle the increased cooling needs. They also need to monitor the conditions of the new racks and plan for future expansions.


With each rack producing more hot exhaust air than before, the hot-aisle containment system (HACS) became the preferred solution by the customer. The HACS are designed to contain the hot exhaust air and prevent it from mixing with the cold air in the data center.

Each of the two HACS was designed with in-row cooling units that recycle the contained exhaust air back to the front of the servers at a set temperature.  These units will handle all of the cooling capacity needed for the high-capacity racks and are thermally neutral to the existing room-based cooling.  Another advantage of the in-row cooling units is that they distribute cold air evenly from the bottom of the rack to the top, ensuring all of the high-density servers receive equal inlet temperatures.

Johnston Technologies provided an APC EcoAisle Containment solution that utilized drop-out ceiling panels and meat curtains to contain the air in the row. The containment solution will still allow fire suppression systems to do their job by automatically dropping the ceiling panels above the contained area if the temperature and smoke detectors are triggered.

For each pod, we provided new APC racks, advanced metered rack power distribution units (rPDUs), and environmental sensors. Each three-phase rPDU gives our client the agility to increase the rack capacity significantly while providing monitoring abilities.

We also added a StruxureWare network monitoring appliance that teams the rPDUs, in row ACs, and environmental sensors for advanced monitoring capabilities.


Each EcoAisle successfully contains exhaust air from eight high-density racks and is cooling the front of the servers with four in-row AC units. Featuring variable speed fans, the in-row AC’s maximize cooling efficiency by adjusting fan speeds to the demand of the servers in the rack.

The StruxureWare monitoring appliance allows our client to not only ensure everything is working properly (and at maximum efficiency), it also allows them to control the rPDUs remotely and plan for future growth. Their new capacity planning capabilities will allow them to accurately design additions and changes to their data center without affecting the live load.

By converting 16 racks using traditional rack-mounted servers to high-density servers, each rack can now compute exponentially more data than they once were capable. This concentration will allow the customer to expand their abilities within their existing data center and without sacrificing floor space to do so.

The only additional floor space used was taken by the eight in-row AC units.  However, it prevented the need for bulky CRAC units to handle the cooling needs.  Furthermore, the space they save by converting each of the traditional racks to high density racks will more than make up for the additional space used.
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