Benefits and Lessons Learned From Chiller Upgrade Projecttest

By Dan Hounsell, Editor

November 2014

The chiller plant upgrade brought wide-ranging benefits to the facility.

“The project allowed the county to save a significant amount of money in the first cost of equipment,” Comayagua says. “It also allows the system to operate closer to the real building load profile, which improves operational efficiency and optimizes the runtime on the chiller compressors. The revision to a variable primary flow system further improves the system efficiency by allowing the chiller and pumps to throttle down even further to match the actual building load.”

The new equipment got its first test in June 2011.

“We experienced several days of design day conditions,” Comayagua says. “During this time, only two chillers running at 85 percent were needed to support the building’s cooling loads. This translates into approximately 1,000 tons of cooling. The system was revised to continue the N+1 redundancy successfully because the third chiller was not needed at peak conditions and could continue as a standby unit.”

 After four years in service, the upgraded chillers, cooling towers, and pumps are performing reliably and delivering efficiency.

“The estimated electrical savings is 900,000 kWh, resulting in 530 metric tons of carbon dioxide emissions prevented,” Comayagua says. “The electrical cost savings are approximately $50,000 annually.”

But the upgrade’s benefits have gone well beyond the county’s utility bill and bottom line.

“The project included installation of tower water treatment,” he says. “This has resulted in a more efficient system that requires less maintenance.”

To ensure the equipment’s long-term performance, the project’s contractor is continuing to provide support for the plant.

“Equipment maintenance and preventive maintenance are performed by a service contractor,” Comayagua says, adding, “training, operations and maintenance manuals, and as-built plans were provided to the department’s operations and maintenance staff at the conclusion of the project. Ongoing training is provided to maintenance staff via service contractor.”

Four years after completion, the county continues to feel the positive impact of the chiller plant upgrade.

“Overall, this project was beneficial,” Comayagua says. “The new equipment is more efficient, reliable and provides needed redundancy. In addition, the project provided for the elimination of R-11 refrigerant. Significant benefits also have been realized through the projects building automation systems upgrade.”