Strategies for Evaluating Data Center Aisle Containment, Part Two

Todd Boucher is the Principal and Founder of Leading Edge Design Group (@ledesigngroup), a critical infrastructure firm that specializes in designing, building, and maintaining Data Center, LED Lighting, and Information and Communications Technology systems.

In the first part of this blog, we reviewed common data center challenges that are creating a need for aisle containment, how an aisle containment solution can help an owner gain back capacity in their data center, and some vendor-neutral strategies for evaluating containment solutions. Here, we will review peripheral project costs that have the potential to impact the project budget and strategy of an aisle containment solution.

Review Peripheral Project Costs

For most retrofit projects, there are typically required costs outside of the aisle containment system itself that will impact your overall implementation budget. It is important to review your existing data center to determine how these peripheral items will add to your project budget.

Fire Protection

Creating a fully encapsulated cold or hot aisle containment system may require modifications to your fire protection system, which could include additional detection and suppression inside of your containment area. Even if you are only implementing partial containment (like a vertical wall from the top of your racks to the ceiling) the quantity placement of your fire suppression nozzles may need to be augmented. This is a cost that impacts most aisle containment implementations and should be considered when creating a budget for the project.

Real-Time Data Collection

There are several energy efficiency gains that can be realized through the implementation of aisle containment systems. Most notably, the supply air temperature being delivered from your CRAC units to the server inlet can often be increased. Energy Star states that data centers can save 4-5 percent in energy costs for every 1°F increase in server inlet temperature. However, prior to making server inlet temperature adjustments, it is important that you have the ability to capture relevant data from your data center to understand the real-time environmental impacts of a temperature increase.

Temperature (or combination temperature/relative humidity) sensors should be installed in the cold aisle at the server inlet location (front of the IT equipment racks) to collect real-time server inlet temperature information. These should be installed prior to aisle containment so a baseline and/or trend can be created for your cold aisle. After implementing aisle containment, most data centers will see a decrease in the server inlet temperature due to the reduced air mixing between supply and exhaust air. Once your environment has stabilized, it is recommended that you increase supply temperature incrementally (1°F or 2°F at a time) while actively monitoring the server inlet temperature through your sensors.

Sensors can be installed cost effectively either through your Data Center Infrastructure Management (DCIM) system or through an independent monitoring system.

CRAC Unit Controls

In most legacy data centers with multiple Computer Room Air Conditioners (CRACs), the units operate independently, controlling temperature and humidity based on their individual setpoints. This leads to a common data center cooling problem of ‘dueling’ CRAC units, where one CRAC unit is in reheat mode while another adjacent unit is in cooling mode. When implementing aisle containment to an existing data center with perimeter CRAC units, it is important to understand the manner in which the CRAC units are controlled. If the units operate independently, a centralized control system should be considered. This will enable the CRAC units to work together as a group and help prevent the inefficiency created by ‘dueling’ units.

Because this strategy and cost are not typically included in aisle containment proposals, it is important that data center operators understand the configuration of their existing CRAC units and integrate the review of the controls system into their evaluation of an aisle containment solution.

Blanking Panels and Sealed Openings

The effectiveness of aisle containment systems is significantly reduced if blanking panels are not installed in IT enclosures and raised floor openings are not sealed. Any open spaces in the IT racks or openings for cable cutouts in the raised floor increase air mixing and prohibits a proper segregation of cool supply air from hot exhaust air. Implementing blanking panels and sealing raised floor openings is a simple, cost effective initiative that should be completed prior to implementing any aisle containment solution.

Completing a thorough review of your own data center, determining what modifications you are willing to make (if any) as part of a containment project, and understanding what peripheral costs may impact your project budget will enable you to complete a vendor-neutral review of aisle containment solutions and effectively determine which is best for your unique data center.

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