The DuPage County Governmental Complex is comprised of 12 buildings totaling 1.5 million square feet.
WHEATON, IL — “On the hottest day of the year, we’ve got 1,000 tons of chiller capacity in reserve. That helps me feel secure,” said Dan Baran, facilities supervisor of power plant operations at the DuPage County Governmental Complex in Wheaton. Baran was discussing the recent upgrade of the chiller plant and chilled water distribution system on the government campus.

The upgrade project involved replacing three single-stage centrifugal chillers ranging in age from 18 to 30 years and totaling 3,300 tons of capacity. According to Baran, the reasons for replacement were a desire for greater efficiency, concern about the R-11, -12 and -114 refrigerants used in the old machines, and an increasing concern about unit reliability because of age.

The plant includes 1,000- and 2,000-ton centrifugal chillers and a 1,150-ton absorption chiller.
Electric chillers were chosen for the upgrade, including a 1,000-ton Trane CenTraVac™ centrifugal chiller and a 2,000-ton Trane duplex CenTraVac machine. Also used is a 1,150-ton Trane Horizon™ two-stage absorption chiller. All chillers are connected in parallel and can be operated in any combination, serving cooling load directly or delivering chilled water to the 1.2 million-gallon chilled water storage tank.

Another important part of the upgrade was the installation of a system-wide Tracer Summit?control system. This allows optimization of the chiller plant and distribution system, and provides an opportunity to observe system conditions from the chiller plant control room or from remote locations.

According to Baran, the system flexibility allows him to quickly respond to changing energy prices or supply conditions. He added, “The system performs like a champ.”

Publication date: 07/29/2002