Case Study - Offices

Pasadena Corporate Center

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OFFICE GETS TRANE CHILLER THAT’S SO EFFICIENT IT EVEN SAVES NEIGHBORS MONEY.

AN OFFICE’S NEW TRANE CHILLER OPTIMIZES THE PERFORMANCE OF A NEIGHBORING CHILLER, TOO

TRANE HORIZON CHILLERS OFTEN MAKE THE MOST SENSE, SOMETIMES FOR SURPRISING REASONS.

The Pasadena Corporate Center (PCC) is a group of office buildings, recently purchased by the Aetna Life Insurance Company and identified by their prime business district address in Pasadena: South Lake Avenue. In reviewing the building at #251 South Lake during the acquisition process it was determined the building would need a new chiller. The building dated to 1970 and had its original steam-fired absorption chillers that were now unreliable and inefficient. John Haviland, Director of Engineering for Marx/Okubo Associates Ltd., the consulting firm representing the owners, recommended a Trane Horizon™ direct-fired absorption chiller because Haviland said, “The owners thought that absorption made the most sense for this building.” But there was also one more reason that makes this story particularly noteworthy.

A TWO-FOR-ONE UPGRADE.

One of the adjacent buildings was built in 1980 and had been served by three 225-ton single-stage electric centrifugal machines. These machines were still in relatively good conditions but their operating costs were somewhat higher than desirable. This was, in part, created by the electricity requirements of the chillers during peak hours. According to Haviland an idea was advanced to size the chiller at the #251 building slightly larger, then tie the two buildings’ chiller plants together, so they could both benefit from the economies of the absorption system. The #251 building has a wide range of chilled water demand from a peak of 700 tons on a hot summer workday to a low of 70 tons on spring and fall evenings. This load profile indicated that two 440-ton Trane Horizon direct-fired absorption chillers would produce sufficient extra capacity for the neighboring building.

INCREASED PEFORMANCE, REDUCED COSTS—IT’S THE TRANE WAY, EVEN WHEN IT’S UNUSUAL.

Once the two central plants were integrated and a shared building automation system was installed, total operating costs were immediately reduced, reliability was improved, and PCC had more flexibility in dealing with changing energy prices. The lower chilled-water temperature the absorption equipment generates also improves the airside equipment in both buildings. David Ellner from Engineered Automation Systems, Inc, the firm that did much of the detailed engineering for the project, noted that previously the neighboring building had to use two of its three centrifugal chillers to carry a summer load, now this load can be carried by only one machine. “As a result of these upgrades this should be one of the most energy efficient buildings in Southern California,” he said. As with many Trane projects, economic payback is important as well—and that should come quickly for PCC. As Brett Gaviglio, a Trane Sales Engineer notes, “With the absorbers on line, (the owners) can expect annual energy cost to drop dramatically most months of the year.”