FRAMINGHAM, Mass., and AUSTIN, Texas — Ameresco Inc. announced that it has started work on an energy savings performance contract (ESPC) for Austin Energy’s Domain District Cooling Plant. The $5.2 million project includes the installation of a new chilled water storage system that will help reduce the plant’s peak electricity usage by shifting the chilled water load and associated electric consumption from on-peak to off-peak hours.

“Austin Energy has the top performing renewable energy program along with the first and largest green building program in the nation,” said Dennis Lilley, Austin Energy. “Ameresco’s expertise has allowed us to continue to build on this record of energy efficiency as we work to identify areas in which we can lower electricity costs and reduce expenses for the city and our customers.”

As the nation’s eighth largest community-owned electric utility, Austin Energy serves 425,000 residents in Austin, Travis, and Williamson Counties. Austin Energy’s district cooling plant installs and maintains the piping and heat exchangers that distribute chilled water from its plant to individual buildings via a network of underground pipes.

Prior to starting the work on the ESPC, Ameresco performed a comprehensive audit and identified energy savings measures at the Domain District Cooling Plant, which will include the installation of a 24,000-ton-hour chilled water storage system large enough to shift a major portion of the chilled water load from on-peak to off-peak over a four-hour period. The upgraded system will be comprised of a 2.4 million gallon concrete thermal energy storage (TES) tank, 92 feet in diameter by 48 feet in height. The system circulation will be maintained by three 200-horsepower horizontal splitcase pumps controlled by variable frequency drives.

The new energy management system will be upgraded to control and monitor the new TES system along with upgrades to the existing plant controls. New mechanical piping and associated mechanical devices will connect the new pumps to the TES tank.

“We are excited to partner with Austin Energy to install measures that will improve the electric load profile of the facilities and build upon their strong history and commitment to energy conservation,” said Bob Georgeoff, vice president, Ameresco. “Under the ESPC model, Ameresco coordinates the upfront project costs and the city repays that investment with their savings over time. This model enables the city to benefit from budget-neutral upgrades by guaranteeing a minimum level of savings over the term of the contract.”

The Domain District Cooling Plant is located in northwest Austin and provides continuous cooling services to a mix of industrial, retail, office, and residential customers. The project is expected to be completed by December 2013.

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Publication date: 3/4/2013