How best to deal with heat generated by high-density equipment and power usage can be cause for concern. Generally, the more kit that can fit into a small space the better, but reaching consensus about how to control temperature involves guesswork. Cold aisle containment is one way to keep dense environments cool and reduce the risk of down time caused by overheating components.

Short airflow paths
Cold aisle containment encloses the cold aisle and prevents the mix of cold air and hot exhaust air. It ensures climate control units keep the airflow path as short as possible – improving the efficiency of the computer room air conditioning system and limiting the energy it demands.

By controlling the air temperature, server components at board level are kept within specified temperature and/or humidity ranges. Cold aisle containment can also be used with inline heat exchangers, so that even higher heat loads per enclosure can be dissipated. The units extract the air from the warm passages then blow it, cooled, into the cold aisle.

In contrast, hot aisle containment allows critical cold air to spread into the general data hall, which can negatively dissipate cooling energy, slowing the effective cooling response and taking longer to reduce server temperature. Cold aisle containment enables a faster cooling response to sudden increases in heat load because the air is not spread into the data hall surroundings but closely contained, directly at the server inlet zone.

Intel has invested in developing its server chips to integrate with third-party cooling systems. Cooling systems are central to any healthy IT system and, while down time should be avoided, the associated cost and how to cut carbon emissions should be considered. 

This is why vertical aisle containment is now being used. It offers a cost-effective, easily maintained solution to air routing and containment for all types of racks by ensuring that the airflow is maintained in the correct direction and at full velocity.

But containing airflow in a vertical direction – with the hot air rising and the cold air falling – can pose a challenge.

If the airflow leaks into adjacent compartments, the efficiency level of a given aisle starts to fall because more energy is required to ensure an adequate airflow is maintained. Manufacturers have carried out onsite testing to help keep energy costs to a minimum and hardware at its optimum temperature.

Live flexibility
Moves, adds and changes to installed equipment in these confined spaces can prove problematic. Free form aisle containment can offer flexibility and the chance to swap out complete racks, in a live, fully operational data center. Structured cabling and airflow system containment are linked to create a single integrated solution that features adjustable vertical closure panels, support for legacy technologies and a low-energy footprint. The technology supports a free-standing aisle infrastructure, and underpins the overhead panels above the aisle without being individually dedicated to any rack.

When carrying out work there is no disturbance to the cold aisle containment infrastructure, which remains in place and functional, and all rack-mounted cable raceway also remains undisturbed. Legacy systems support means that where old rack installations exist, the free form aisle containment technology can offer a cost-effective retrofit aisle cocooning solution

Potential challenges
Configuring a cold aisle containment system for a new data center should be relatively straightforward because it allows specification of uniform products designed to work together. However, there are some issues to note:

- All data center environments evolve and cabinets and racks are no exception with their mix of depths, widths and heights. Cabinets with raised feet for levelling can create a backwash of air underneath them, while there may be gaps either down the sides or where there is missing equipment. Although blanking plates should cover these, they may not be in place, leading to a mix of hot and cold air.

- A retrofitted cold aisle containment system involves fixing the ceiling eyebrow to the top of the cabinets, installing ceiling panels, fitting air skirts under and between the cabinets if necessary, and attaching the doors at both ends of the aisle. This ensures that the cold air emitted from the floor is sealed in a cocoon which is unaffected by hot exhaust air, while the cooling air can only exit through the equipment for which it is intended. It is also likely that the floor will need attention and changes to accommodate the weight of any containment system may also have to be made. Floor tiles can also degrade and break, and replacement tiles may not be the right size.

No air containment system can be effective if there are areas where leaks can occur, so this too will need to be addressed.

This article first appeared in FOCUS on Cooling, in Issue 35 of the magazine. To read the full digital edition, click here.