Cooler in Columbia

Buford Goff and Associates, was selected for a chiller plant upgrade for the South Carolina Department of Mental Health in Columbia, SC. The existing chiller plant included a 1,200-ton and a 750-ton centrifugal water cooled chiller, a 1,200-ton and a 750-ton cooling tower, and associated pumps and accessories. The cooling towers were relatively new, but the chillers and chiller pumps were more than 30 years old. The primary pumps were located in the chiller plant and the secondary pumps were located in a pump room at each campus. The new chiller sizes considered were three 600-ton water cooled chillers, two 1,200-ton water cooled chillers, or two 750-ton water cooled chillers with a 400-ton air cooled chiller. Since a variable flow primary system was selected and all existing chilled control valves were three-way, all valves which had been replaced in the past few years had to be replaced with new two-way valves. The first phase of the project involved installing isolation valves on the existing chilled water lines from the 20-in header. Before the work could be done, glue containing asbestos was discovered on the header insulation. Structural steel for pipe supports was installed as well as the first primary pump and the first 1,200-ton chiller. The next phase involved installing the remainder of the needed isolation valves. These shutdowns were selected for the coolest evenings predicted by the weather service. After the first new 1,200-ton chiller was in operation for approximately two weeks, everyone was comfortable with its operation, and the contractor proceeded in removing the existing 1,200-ton chiller.