Consulting-Specifying Engineer - December 2008 - (Page 35)

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// the Bay’s delicate saltwater balance. To educate area residents, City Hall offered a class on recycled water. ATCG jumped on the idea, but then had to convince the city that it was in the city’s best interest to dig up streets to add a branch line to ATCG’s location in Santa Clara. “We went on Google Earth and showed the city that the whole area around the job site was marked with data centers,” Chadwick said. “We convinced the city they could get a lot of users if they just built the line.” Part of that approval resulted from ATCG’s reminder that data centers draw water and power 24 hours a day, seven days a week, unlike a typical office building that experiences high demand only from 8 a.m. to 6 p.m. during the work week. After it received the South Bay Water District’s approval, ATCG had to convince an engineer in the Environmental Service Dept. that a reclaimed water line to the area was a good idea as well. Following that hurdle came a special meeting with the state health department. “They were worried about cross connections and how the drinking water could be affected by the reclaimed water,” said Chadwick. So ATCG submitted, on four different occasions, sets of drawings and site plans that showed how it would protect the water supplied—which included separating buried drinking water and reclaimed water pipes by 2 ft to make sure leaking water couldn’t The data center required redundant air-handling systems. come near the drinking supply. An in-house team of four to five Equinix engineers assisted ATCG in the process. The time-consuming process lasted from July 2007 until March 2008, but the end result was worth the trouble. Equinix needed only two water storage tanks—at 20,000 gal and 10,000 gal—saving it from adding a new 30,000-gal storage tank. This saved Equinix $300,000 in construction costs alone. The project also provided secondary savings since reclaimed water costs approximately 35% less than standard domestic water. Another cost-savings concept came to light when ATCG added rooftop air handlers with an air-side economizer. Northern California’s climate is ideal because temperature extremes are rare. Although adding an air-side economizer initially costs more, the annual savings of $318,000 per year meant in less than four years Equinix could recoup its costs and start saving money. The units also are equipped with atomizing humidifiers with RO water makeup that avoid the wasted energy associated with electric steam humidifiers and also provide the added benefit of free cooling when in use. Because the data center required redundant air-handling systems to assure reliability in the event of a failure, ATCG was able to adjust the control sequence and added variable frequency drives (VFDs) to operate all air handlers at a reduced airflow rate. As a result, there was less of a pressure drop through each device and a net savings of 18% hp per fan, more than $51,000 a year in electrical savings. The indoor ductwork system includes VAV distribution to the equipment. Notice the orange VESDA smoke detection system routed at the underside of the roof. All photos: Alfa Tech Cambridge Group The 40,000-gal underground chilled water storage tank is being readied for installation in the pit. The 18-in. chilled water piping connection was re-routed to the new storage tank. Consulting-Specifying Engineer • DECEMBER 2008 35

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Consulting-Specifying Engineer - December 2008 Contents Viewpoint News M/E Roundtable ARC Awards New Construction Gold New Construction Silver New Construction Bronze Renovation Gold Renovation Silver A Green Approach to Air Conditioning Systems Turning Down the Lights Case Study New Products Equipment Lifecycles Advertiser Index Green Space Gas Technology Pure Power Supplement

Consulting-Specifying Engineer - December 2008

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