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FIGURE 1. Day 1 data-center configuration.

As previously discussed, establishing the Day 1 load profile, as well as a sense for multiple generations of IT equipment, is critical. Using these profiles and projections, a phased approach can be implemented. Figure 1 provides an example of a Day 1 layout of a data center. Notice it has allocated space not only for future equipment racks, but future cooling units (CRAC units).

FIGURE 2. Interim data-center upgrade.

Note that there are two CRAC units to provide 100-percent redundancy and/or partial load capacity. Further, note that the CRAC units discharge under the floor in the hot aisle to avoid the venture effect of perforated tiles too near to CRAC units. Figure 2 shows an example of the first two rows of racks being populated, while Figure 3 shows all rows (racks) being populated and the addition of two CRAC units.

FIGURE 3. Fully configured data center.

There are various ways of providing for the future, including space only, space/power roughing, and space/power roughing/piping roughing. The choice is based on economics and level of disruption when the upgrades or expansions occur.

PROCEDURE ROOMS

Unlike data centers, the equipment used for procedure rooms, such as X-ray/imaging, magnetic resonance imaging, positron emission tomography, and computed tomography, are not standardized. They can vary significantly in shape, interface requirements, and configuration from manufacturer to manufacturer.

There can be a wide variety of challenges associated with this equipment, the rooms, and suites, such as air change, velocity, particulate, electromagnetic interference, and noise. For redundancy, sometimes a good approach is to have one cooling source be from a central system and the other be a localized unit.

SUMMARY

Some key points to remember include:

• Cooling equipment can see four to five generations of IT equipment. Therefore, allow for major changes in need and operation.

• ASHRAE datacom books can be a source of information for technology cooling.

• It is critical to identify the level of redundancy required.

• It is critical to identify the full load profile (part load and full load), as well as current and future loads.

The president of DLB Associates Consulting Engineers and a member of HPAC Engineering's Editorial Advisory Board, Don Beaty, PE, FASHRAE, was chair of American Society of Heating, Refrigerating and Air-Conditioning Engineers Technical Committee 9.9, Mission Critical Facilities, Technology Spaces and Electronic Equipment, from its inception through June 2006.

ASHRAE Datacom Books

American Society of Heating, Refrigerating and Air-Conditioning Engineers Technical Committee 9.9, Mission Critical Facilities, Technology Spaces and Electronic Equipment, has published a series of books on data-processing and communications (datacom) facilities:

• “Thermal Guidelines for Data Processing Environments, 2nd Edition” (2009): Covers industry-endorsed environmental specifications, temperature- and humidity-measurement location, and actual, rather than nameplate, load.

• “Datacom Equipment Power Trends and Cooling Applications” (2005): Provides trend curves for maximum load of network equipment, servers, etc.

• “Design Considerations for Datacom Equipment Centers” (2005): Covers basics of data-center design, including HVAC, fire protection, and commissioning.

• “Liquid Cooling Guidelines for Datacom Equipment Centers” (2006): Discusses liquid-cooling basics and performance considerations, provides vendor-neutral architectures, and compares the efficiencies of air and liquid cooling.

• “Structural and Vibration Guidelines for Datacom Equipment Centers” (2008): A nontechnical look at serious structural and vibration challenges concerning today's data centers, it provides basic structural criteria for floor and raised-floor capacities.

• “Best Practices for Datacom Facility Energy Efficiency” (2008): Discusses water- and air-side-economizer basics and guidelines.

• “High Density Data Centers — Case Studies and Best Practices” (2008): Discusses 11 high-density installations, including overhead cooling, computer-room air conditioning, in-row cooling, and in-rack cooling, and establishes benchmarking and field data-collecting techniques.

To purchase these books, go to www.ashrae.org/bookstore.