Overview
Touted as the “World’s Marketplace,” eBay is the largest online auction firm. This four-story 135,000 SF Tier IV Data Center was designed to reliably support their immense data needs. The outdoor equipment yards house eight 2MW Generators, a 200,000-gallon chilled water storage tank, and a hydro-pneumatic well tank (for back-up cooling tower make-up water). Floors one and two house the building’s entire infrastructure (switchgear, UPS, batteries, chillers, and pump rooms), while the two upper floors are completely dedicated to raised floor computing space. Phase 3 consisted of the design-build fit-out the 35,000 SF 3rd floor for computing space, and completing the necessary infrastructure (incorporating 2,600-ton chillers and associated cooling towers, pumps, piping, controls, etc.)
The chilled water system consists of six 600-ton centrifugal chillers in an N+2 arrangement (2,400-ton demand served by 3,600 tons of capacity). Each chiller line-up consists of a primary CHW pump, chiller, condenser water pump, and cooling tower (2-cell forced draft with sound attenuation mounted on the roof). The primary CHW circulates throughout the 1st floor to each of two dedicated secondary CHW pump rooms (A & B). Each Secondary CHW lineup consists of three pumps each capable of handling 50% of the building’s total demand. That is to say, the CHW distribution consists of redundant N+1 pump rooms, each supplying CHW via 12” risers to each of the computer room floors (either set of risers can handle the entire building load).
The computer room floors are designed for 100 w/SF load density, with the racks arranged in a Hot Aisle – Cold Aisle configuration. To satisfy this cooling demand, six rows of 30-ton CRAHs (42 per floor) are distributed throughout each floor in a cascading arrangement. CHW is distributed beneath the 36”high raised access floor to each of the CRAH units. Computational Fluid Dynamics (CFD Modeling) was utilized during the design to validate this design approach.
Ventilation for the Computer Room Floors is provided from four 100% OA packaged DX rooftop units, complete with duct mounted humidification. Computer Room humidity levels are maintained via centralized recirculating air system on each floor, consisting of redundant fans, and redundant wall mounted humidifiers.
The controls for the Building Management System were also designed with reliability in mind. The wall-mounted control panels located throughout each computer floor are fully redundant and the wiring distribution (from panel to device) is arranged in a “checker board” configuration (each panel serves every other device). Additionally, the CHW plant is designed with redundant critical sensors. To avoid unwanted automated system shut-downs (as a result of a faulty sensor), two sensors are furnished in critical areas, and both must signal for a change in operational sequence.
To ensure that the installed systems fully comply with the design intent, BKM fully participated in the Factory Witness Testing of the Chillers and CRAH units, as well as weekly construction progress meetings and monthly site inspections. As the project neared completion, BKM assisted with Commissioning, including Site Acceptance Testing (verifying each piece of equipment was installed properly; factory start-up was performed, and the controls are working properly). This testing was followed by the Integrated Testing (3,400 kW of load banks were brought onto the floor to simulate the cooling demand, and the building’s performance was fully verified). The Integrated Testing also included simulation of various failure modes to ensure the system’s reliability.
