Project Description: Cooling Tower Replacement
Client:
The Washington Post
Washington, DC
Facts:
- Size: 2,000 square feet (approximate project area)
- Project Type: Facility Infrastructure Upgrade
- Construction Cost: $1.1 million
- General Contractor: PBM Mechanical, Inc.
- Architect: SmithGroup
- Services Provided: Project Management; Mechanical and Electrical Evaluations and Designs; Construction Documents; Contractor Selection; and Construction Administration
The existing 3,000 ton cooling towers were in poor condition after 35 years of continuous service despite the rigorous maintenance procedures performed by The Washington Post. Williams Notaro evaluated the future requirements of the facility as well as the impact of the future replacement of the central plant cooling systems and developed a replacement plan for the existing cooling towers.
To reflect the elimination of the printing plant in the facility as well as conversion of much of the original industrial areas in the building to office space, a new 2,000 ton cooling tower was selected. Williams Notaro arranged and attended factory visits for the facilities personnel to review and evaluate different cooling towers. Williams Notaro then prepared specification and bid packaged for two manufacturers and assisted in the bid review and final selection of the stainless steel Evapco 4-cell tower.
Energy efficiency was a major concern in the design of the new cooling tower system. A condenser water temperature difference of 15°F was selected, instead of the industry standard temperature difference of 10°F, to minimize fan and pumping horsepower. The new towers were carefully arranged to maximize the accessibility to each tower for repair and maintenance. A special heavy duty catwalk, meeting OSHA safety standards was design to allow the heaviest components of the towers to be set on the catwalk. The towers were specified with removable jibs and sliding motor mounting assemblies to minimize the time required to change fan motors.
To further reduce the pumping system power requirements, the existing piping was retained where ever possible. Originally designed for 9,000 gpm, the piping pressure drop was minimal at the design flow rate of 4,000 gpm. The existing condenser water pumps would ultimately be replaced and down sized significantly during the upcoming Central Plant Replacement project.
Williams Notaro was the prime design contractor and Project Manager for this project and was intimately involved in the rigging and construction planning process to minimize the impact on the operation of The Washington Post. The demolition of the existing cooling towers and the construction of the new towers and associated work were completed in less than 3 months. The new system was fully tested and operational before the cooling season and did not adversely impact the operation of this 24 hours/day operating facility.
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