ACHRNEWS

Chiller Upgrades Control Energy Usage

May 10, 2010
This readout shows real time plant operating efficiency, daily and monthly dollars saved, and CO2 reduction levels. (See images above and below.) It is accessible to both technical staff at the airports and to engineers at Optimum Energy, which supplied the software.

Airport expansions are financed, in part, by user fees and federal capital grants. So those providing such funding want to be sure money is spent well.

Hotel operators, restaurant owners, and office renters in a commercial complex want to be sure the money they are paying out is being spent wisely.

College administrators, more than ever, are watching every dollar as state funding issues arise.

And, all three sectors are caught up in the need for environmental correctness.

One aspect of counting dollars and staying green ties in with the HVACR equipment especially the large chiller plants common at airports, commercial buildings, and college campuses.

In the three brief case histories that follow, improvements and upgrades to chiller operations are described. The information comes from Optimum Energy LLC, which was involved in all three projects.

AIRPORT

As part of Mineta San Jose International Airport’s terminal modernization program begun in 2007 and scheduled to be completed this year, airport officials made a commitment to achieve Leadership in Energy and Environmental Design (LEED) certification for its new facilities and to implement energy-efficiency technologies that would help reduce operating costs. The program calls for upgrades to Terminal A and construction of a Terminal B, the latter with a 380,000-square-foot concourse.

Improvements at the central plant included the addition of a 1,100-ton chiller with upgrades to the two existing 450-ton chillers, including variable-frequency drives, a new cooling tower, and adjustments to existing air-handling units. Once that was completed and to allow continuous commissioning, Optimum Energy’s OptimumLOOP software, part of OptimumHVAC, was installed and commissioned through the airport’s building automation system. Reductions in energy consumption were noted and verified with OptimumMVM, a service that allows facility managers to remotely measure, verify, and manage equipment operations and savings through a secure online portal.

RETAIL

The 250,000-square-foot Aventine complex in La Jolila, Calif., has offices, restaurants, and a hotel. Owners were interested in finding ways to lower operating costs, reducing environmental impact, and seeking LEED certification.

A feasibility study pointed to upgrading to an all-variable-speed chiller plant that, like the San Jose airport project, used OptimumHVAC software. The La Jolila project retained the two existing centrifugal chillers. The ROI was projected to be less than three years, according to a statement from Optimum Energy.

The actual project involved converting the centrifugal chiller plant to a primary-only, all-variable-speed system and retrofitting the two 300-ton chillers with oilless variable-frequency drive centrifugal compressors. In its bid for LEED, those involved in the Aventine project focused on recognition in the Existing Building (EB) category, with special attention paid to credits for optimizing energy-efficiency performance.

CAMPUS

The University of LaVerne in Southern California has expanded throughout the years and currently has 11 buildings drawing HVAC needs from a central plant. The most recent upgrade included the addition of a chiller and reconfiguration of the primary/secondary-pumping loop to an all-variable speed/primary-only system.

The expanded plant is designed to operate 12 to 14 hours per day, five to seven days a week. It consists of one 400-ton chiller, one 390-ton chiller, two 685-gpm chilled-water pumps, two 1,200-gpm condensing water pumps and two 1,200-gpm cooling towers.

OptimumLOOP optimization software was added to automatically and continuously gather information about campus building loads and match chilled-water supply to demand by controlling pump and chiller speeds.

For more information, visit www.optimumenergyhvac.com.

Publication date: 05/10/2010