Arup Chiller Replacement Project Recognized for Energy Efficient Improvements

Energy savings equivalent to 8M pounds of carbon dioxide

Jun 17, 2013, 14:36 ET from Arup

SAN FRANCISCO, June 17, 2013 /PRNewswire/ -- An Arup-designed chilled-water system at UC San Francisco has earned a $757,000 energy efficiency award from PG&E, and a 2013 Higher Education Energy Efficiency and Sustainability Best Practice Award in the HVAC Retrofit category.

The $7.7 million project for the UCSF Medical Center, which Arup designed and completed in January, 2013, shifted the cooling production 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 $1.3M in utility costs, more than $100,000 in maintenance costs, and a simple payback of less than 6 years.

The resulting efficiency 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 with a reputation for delivering innovative and sustainable designs, 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 unreliable and 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% 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, dysfunctional 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 using stents (similar to the concept of heart surgery) that allowed specialty contractors and pipe-fitters to work on parts of the chilled water lines while water flowed through the bypass lines. 

Within an operating hospital under California's stringent OSHPD jurisdiction, Arup helped reduce operations and maintenance costs, utility costs, and green-house gas (GHG) emissions, while greatly improving service reliability, system performance, and cooling capacity for future growth.  

Projects recognized in the HVAC Design/Retrofit category of the Higher Education Energy Efficiency and Sustainability Best Practice awards program should demonstrate leadership in HVAC equipment selection, distribution system design, and controls specifications. The goals of the program, made possible by the Higher Education Energy Efficiency Partnership, are:

  • To highlight the achievements that California campuses have made through innovative and effective energy efficiency projects and sustainable operations;
  • To showcase specific projects as models to be used by other campuses to achieve energy efficiency and sustainability goals; and
  • To provide campus staff with a compendium of best practice projects that can be transferable to their campuses.

Project team members include:

  • Prime Consultant: Arup
  • Construction Manager: Jtec HCM
  • Prime Contractor: City Building
  • Mechanical Contractor: Southland Industries
  • Mechanical Engineer: Arup
  • Electrical Engineer: Cammisa and Wipf
  • Structural Engineer: Estructure
  • Architect: The Design Partnership
  • Hydraulic Modeler: R&A Engineering Solutions
  • Acoustical Consultant: Arup

About Arup
Arup is the creative force at the heart of many of the world's most prominent projects in the built environment and across industry. Its engineers and consultants deliver innovative projects across the world. Arup opened its first US office 25 years ago, and now employs 1,000 in the Americas. The firm was founded in 1946 with an enduring set of values that fosters a distinctive culture, intellectual independence and collaborative approach. The people at Arup are driven to find a better way to deliver better solutions for their clients. (


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