Data Center Qualifications

Power Systems : The philosophy of design for the data center power systems is either a radial or a distributed distribution system. Radial systems are used less frequently and typically on smaller facilities of less than 4,000 amps because of the high cost and size of equipment above 4,000 amps. Distributed distribution systems provide the opportunity to disperse power and keep equipment under 3000 amps and generator sets to a maximum size of 2 megawatts. The distributed distribution system is more reliable since a single point of failure will not necessarily bring down an entire system. A distributed system must be properly designed to include UPS loads, and HVAC loads to generator ability to start these loads. HVAC loads must be evenly spread across the distributed power busses to balance loads and ensure that all HVAC units serving an area are not taken offline when one bus goes down. Owner preference may be for use of PDUs or individual transformers and panels to distribute power to power strips on individual racks. Monitoring and power management can be done at rack level or 480-volt level with significant cost variation. HVAC Systems : The philosophy of design for the data center cooling systems is primarily dependent on three things: local codes; the physical restraints and opportunities of the facilities such as the ability to place equipment in an exterior yard or on the roof; and the preferences of the data center operator. AlfaTech designs have included: on floor CRAC units with DX cooling in yards and on roofs; CRAH units with chilled water cooling using both air-cooled chillers and dry coolers located in yards and on roofs; rooftop air-cooled package air handling units serving air through duct down to underfloor; interior mezzanine located air handlers with ducted air down to the floor; rooftop air cooled chillers to provide cooling; and floor-mounted built-up air handlers supplying air underfloor. The ideal power-efficient system will incorporate air-side and/or liquid-side economizers to use free cooling, such as fluid-to-fluid heat exchangers, dry coolers, or pumped refrigerant economizers used instead of compressor based systems whenever feasible. Cooling towers and other evaporative-based cooling solutions are a problem due to the necessity of using and storing large quantities of water. If a large source of water is available, such as a lake or groundwater wells, this is a

plausible option. Air discharge pattern to the underfloor or into cabinets can present design problems if improperly implemented, as the venturi effect can pull air from the data room back under the raised floor. Full hot and cold airstream containment strategies are favored whenever feasible to support efficient critical cooling air distribution. Particularly high power density facilities may even warrant direct liquid-based cooling instead of the more traditional air-based approaches. This is accomplished with liquid-on-the-chip, cold-plate, and liquid immersion cooling systems. At the onset of the project, AlfaTech will present a single point of contact that will coordinate the internal MEP/Technology team as well as be the direct day-to day contact . Nathan Kirby, PE, ATD, LEED AP BD+C is our Mission Critical Practice Leader. He has over 17 years in the industry and he leads the project technical team who have extensive experience working with high end data center programming and design projects. AlfaTech routinely operates at different levels of similar style design teams on international data center projects and therefore uniquely understand the roles and responsibilities of each team member. In our role as supporting team members to the Coordinated Project Delivery Team, our role is to serve as the Data Center subject matter expert to support and facilitate the flow of information from the client to the design team members. Where necessary, our expertise is used to advise and recommend strategies and approaches to design based on our extensive industry experience.

DATA CENTER PROGRAMMING