July 1, 2013: Chilled Water Retrofit Earns Energy Efficiency Awards
Projected Annual Savings of $1.3 Million in Utility Costs
The $7.7 million project for the UCSF Medical Center, which Arup designed and completed in January 2013, shifted cooling from old, inefficient absorption chillers, to new high-efficiency electric chillers, and upgraded the chilled water distribution system to both hospitals on the campus. As a result, the project was confirmed by PG&E to save more than 65M kBtu of energy per year, with a projected annual savings of $1.3 million in utility costs, more than $100,000 in maintenance costs, and a simple payback of less than 6 years.
The resulting PG&E award represents the largest energy efficiency rebate for a single project at the university.
“It is uncommon in today’s business climate that an institution has the vision and patience to execute a project in a manner that defines best practice,” said Michael Sweeney, Building Retrofit practice leader at Arup. “What was traditionally viewed as an impending but necessary project has turned into an economic opportunity that allowed the medical center to take funds traditionally spent on utilities and divert them towards a renewal of vital infrastructure. It’s commendable.”
Arup, a multidisciplinary engineering and consulting firm, was originally hired to help devise a master plan for the chilled-water systems and to identify measurable and actionable improvements. Arup was retained as the prime consultant, leading a team of specialists to implement this Phase I portion of the master plan.
Arup and the hospital recognized early in the planning stage that technological improvements in modern equipment would allow the team to replace just one of the inefficient 385-ton steam-driven absorption chillers with a much larger 600-ton electric centrifugal chiller. Then, by interconnecting the chilled water systems of each hospital, the new chiller could efficiently deliver 95 percent of the annual cooling needs for both. As a result, the reliability and efficiency benefits of the project were doubled to two hospitals.
Arup services included the conversion of the multiple primary-only pumping systems to a common, modernized variable-speed primary/secondary pumping system; detailed infection-control planning for the replacement of major three-way chilled water control valves with two-way valves in and around patient care areas; connection of the chilled water system from one hospital into the upgraded chilled water loop of the other for base load cooling; and the implementation of new control systems that will automate the plant’s operation and calculate energy savings in real-time.
To ensure that the medical center remained operational during these extensive renovations, Arup devised a solution that allowed specialty contractors and pipefitters to work on parts of the chilled water lines while water flowed through bypass lines.
Within an operating hospital under California’s stringent OSHPD jurisdiction, Arup helped reduce operations and maintenance costs, utility costs, and greenhouse gas (GHG) emissions, while improving service reliability, system performance, and cooling capacity for future growth.
For more information, visit www.arup.com.
Publication date: 7/1/2013