As part of a facility upgrade, Waste Management, headquartered in Houston, Texas, replaced its chiller plants to serve its data center facility in Austin, one of two data centers the company operates.
Over time, it had become clear that the two original air-cooled chiller plants in the 2002-built facility needed replacement. The problem was deterioration in the cooling coils of the chillers.
Waste Management hired Alcatex to perform due diligence to examine HVAC solutions. Alcatex called for a chiller replacement at N+N, also known as 2N redundancy, suitable to cover 10,250 square feet of raised-floor data center operations, plus office space and a mechanical, electrical and plumbing service room. Including the data center space, Waste Management’s operations span 40,385 square feet within a 250,000-square-foot building.
Ultimately, Waste Management selected two Daikin 400-ton Pathfinder air-cooled chillers with the highest efficiency available. In addition, the chiller plant includes variable frequency drives (VFD) that add a high power-factor rating without the use of capacitors. The system met Waste Management’s specification for a redundant solution at the 2N level. Additionally, it has four pumps with VFDs to bring 2N+1 redundancy.
During the hot Texas heat in summer 2014, installation of the 12-ton chillers was phased to maintain complete functionality of the data center. Installation took place within two few-hour segments over weekends in June and July 2014. Pre-connections were made in advance so the actual hook-up of each chiller could be expedited. One of the existing chillers was kept running while the first replacement was made. In addition, a temporary rental chiller was available on site as a backup system.
During the chiller-replacement project at the Austin data center, the building automation system was also upgraded. A number of control systems by different manufacturers were integrated into the existing infrastructure. Waste Management replaced the former chiller controls to the ASHRAE-standard BACnet controllers on the Daikin Applied chillers.
Since the chiller replacement was completed in July and the pumps in August 2014, the company has seen about a 10 percent reduction in usage overall at the facility.
Waste Management predicts its annual savings on straight energy usage translates to approximately 11.3 percent or greater, along with a power factor correction savings, resulting in combined savings of more than 13.2 percent annually.