AT&T – Design, Operation, and Recommissioning
Apr 24, 2013
AT&T
Design, Operation, and Recommissioning
Houston, Texas
Since 1985, one of the Principals of sys-tek has completed several projects for this 3,200-ton chiller plant serving a 660,000 square-foot telecommunication facility. The plant operation is extremely critical and in the many years that we have been working in this plant, we have only had two interruptions. The first was caused from a flexible connection failure that was serving a chiller. The second was caused from a flood which put the plant under three feet of water. Projects we have completed include:
Winter Chiller
This project included replacing an existing aged chiller with a new 400-ton centrifugal chiller with variable frequency drive to serve the chiller load during winter operation.
Chiller Plant Upgrade
Under this project we replaced two aging machines with new chillers. The design was preceded by an in-depth load evaluation where the entire facility was computer modeled. Using this model, we evaluated chiller options for size, operation, first cost, and operating cost.
Pumping and Control System Upgrade
From our energy use and modeling knowledge gained from previous projects, we were able to show a significant payback in energy cost by converting the plant to a primary/secondary pumping system. As part of the scope of work, we designed & installed a new control automation system where the pump speeds are adjusted to maintain the desired temperature difference in the secondary loop. This is done by resetting the differential pressure setpoint based on control valve position at the air handling units. This system, designed in 1994, is still in operation today and working as originally intended.
Condenser Water Piping Replacement
The scope of work under this project included detailed design with an emphasis on planning and phasing the project implementation. The project included replacing the condenser water piping system serving the plant from the chillers in the basement to the cooling towers located on the roof of this 180-foot tall facility, without interrupting the operation of the chiller plant itself.
Emergency Response
This project is an example of our ability to respond to emergency situations. In June of 2001, Houston received over 14 inches of rain within a 24-hour period, which ultimately flooded the chiller plant. We were on site within six hours and constructed a 3,000-ton chiller plant outside the building in 36 hours.
