Tower has a ball with energy conservation.

Tower has a ball with energy conservation

A new approach to energy conservation is taking shape in Los Angeles. And that shape is round.

One downtown highrise, the 801 Tower, has incorporated thermal energy storage (TES) technology into its cooling system in the form of ice balls, water-filled plastic balls that are frozen then release cooling energy as they thaw during peak hours.

The ice balls are the latest effort by a Los Angeles business to conserve energy. According to Brian Belier, energy services supervisor for the Los Angeles Department of Water and Power, "Customers now need to learn about methods of conservation and energy efficiency and be encouraged to practice them. Without conservation programs, DWP will likely face capacity shortages by as early as 1996.

According to Belier, over the next twenty years it is anticipated that the successful implementation of the DWP's conservation and energy efficiency programs can produce energy savings equivalent to the output of a new power plant large enough to supply electricity to about one million residential units.

Developers in Los Angeles are beginning to do their part to conserve energy by choosing to install TES systems in their new or retrofitted buildings. Says Scot Duncan, vice president of Retrofit Originality Incorporated (ROI), an engineering firm specializing in energy conservation and TES system design, "TES systems shift peak electrical demand to off-peak periods, allowing utilities to increase overall efficiency by helping to balance peak (afternoon) and off-peak (night) loads; conserving energy through mitigating use of expensive and less efficient peaking systems; and if enough demand is shifted to off-peak periods, deferring or eliminating construction of new power plants."

To encourage installation of TES systems, DWP has developed a thermal energy storage incentive program. Established in 1987, the program offers installation rebates, DWP providing up to 40 percent of the installed system cost or $250 per kilowatt of load permanently shifted to off-peak hours, whichever is lower. This helps offset a higher initial cost required for the TES system compared with conventional systems.

Southern California Edison also offers commercial and industrial customers an off-peak cooling incentives program. Through this program, SCE offers hardware incentives to customers, and co-funds an engineering feasibility study to determine the economic attractiveness of an off-peak cooling application.

Both SCE and DWP offer time-of-use rates which can result in substantial electric bill reductions. These rates provide an additional incentive for the installation of TES systems since their operating costs are much lower than for conventional systems which run during the high-cost peak period of the day. It is inherent for TES systems to operate during the off-peak period when energy charges are less expensive.

At the 24-story 801 Tower, the state-of-the-art $1.1 million TES system will be the first large-scale and most technologically superior system using encapsulated ice ball technology in Los Angeles.

The system, a major component of the building's $5.4 million heating, ventilation, and air conditioning (HVAC) system, will shift more than 2,000 kilowatts of electrical demand from peak to off-peak periods. This will provide enough energy to power approximately 1,500 home air conditioning units, says Duncan.

Mizuhiko Tamura, general manager, R & T Development, developers of the 801 Tower, notes that "combining a TES system with a variable air volume design ensures our tenants will enjoy an efficient, comfortable office environment with complete control of their HVAC system, together with drastically reduced operating costs.

"Since air conditioning is one of the largest components of a building's electrical usage, using a TES system to take advantage of lower off-peak rates is expected to produce a substantial reduction in 801 Tower's operating costs."

TES systems also benefit tenants by helping to insulate them from unknown and projected utility rate escalations. There are currently only five TES systems of significant size in operation in the city of Los Angeles. 801 Tower's TES system is the most advanced, operating on Cryogel encapsulated ice ball technology, rather than chilled water storage.

"The TES system will also protect the tenants from air conditioning equipment failures, since it can provide full air conditioning comfort, even if 50 percent of the main chilling equipment has failed on the hottest day of summer," says Mike Moore, president of Southland Industries, the mechanical contractor installing 801 Tower's air conditioning system. "Buildings without TES do not offer this safety net to tenants."

According to Greg Aden, director of management services for Cushman & Wakefield of Southern California, the 801 Tower's TES system is expected to reduce a large water consumer -- evaporation -- because the building's cooling towers will be used at night when the air temperature is cooler. The TES system should result in a 10 percent water savings. "That translates to approximately 600,000 gallons of water annually for 801 Tower," he concludes.

Takenaka Corporation, prime contractor on 801 Tower, is one of the world's largest design and construction firms. Takenaka has supervised the installation and operation of more than 60 thermal energy storage systems worldwide. Cryogel encapsulated ice ball technology was originally developed in France. The system utilizes thousands of four-inch diameter, water-filled plastic balls which are immersed in a solution of water and antifreeze.

During the night off-peak hours, the system's chillers lower the temperature of the solution to 24 degrees Fahrenheit, freezing the balls and storing energy in the form of ice. During daytime peak hours, the ice melts and cold energy is released into the solution, which is circulated through a building's secondary heat exchanger to provide cooling to the structure.

PHOTO : The 801 Tower (left) uses water-filled plastic balls (below) to save energy and reduce costs. The balls are frozen then thawed to release cooling energy.