G/BA provided design services for a buildout of 30,000 square feet of "shelled" raised-floor area and upgrades for 15,000 square feet of "live" raised-floor area in an existing stand-alone data center, including expansion of the existing central mechanical systems. The design focused on providing new, energy efficient systems, as well as improving the energy efficiency of the existing systems.
In this Tier III data center, all systems are designed with a minimum of N+1 redundancy.
Fifty new chilled water computer room air handlers (CRAHs) cool the new 30,000-square-foot raised-floor area, with a current load of 50 W/sf and future growth capacity to 100 W/sf. The new CRAHs utilize variable airflow control to reduce energy consumption. The CRAH locations and raised-floor air outlet arrangement were determined utilizing CFD modeling. A new air handling unit provides pressurization and low-energy ultrasonic humidification of the raised floor areas.
The addition of three chillers and associated cooling towers resulted in a final plant configuration consisting of six 600-ton electric centrifugal chillers -- four with VFDs -- and nine counter-flow evaporative cooling towers with VFDs. Two 12,000-MBH chilled water plate-and-frame hydronic economizer heat exchangers were added, and modifications were made to the existing hydronic economizer piping to improve performance of the "free-cooling" mode.Operations were optimized through an extensive chilled water system analysis. The existing control sequence was modified to reduce energy consumption. Among the changes: raising chilled water supply temperature, operating VFD chillers at their optimal efficiency range, and optimizing condenser water temperature versus cooling tower fan and pump energy consumption.