When Brookfield Properties purchased Trizec Properties Inc. in 2006, it--along with partner The Blackstone Group--acquired 61 office properties totaling 36 million sq ft in nine U.S. markets, including the 55-story, 1.8-million-sq-ft Bank of America Plaza, one of the most recognizable commercial buildings in downtown Los Angeles.

"When we first evaluated the property, we quickly identified some essential and valuable opportunities to improve the energy efficiency and overall operation of the building," Dave Thompson, general manager of the facility, explained.

Almost immediately, Brookfield set out to improve the long-term performance of the 35-year-old building, investing several million dollars over the course of two years. The investment paid off, as the building received Energy Star certification in late 2008, with Leadership in Energy and Environmental Design for Existing Buildings (LEED-EB) certification expected during the first quarter of 2009.

Energy-Management System

A major step in the overhaul of the building's mechanical systems was the installation of a new energy-management system (EMS). Utilizing efficient direct digital controls, the EMS affords the property team better regulation and monitoring of the building's HVAC-plant fans, pumps, condenser-water and chilled-water plants, and cogeneration plant. Also, it provides building tenants the ability to manually control lighting and temperature and, subsequently, their electricity costs.

While the controls provide tenants more individual control of heating, air conditioning, and ventilation, the EMS allows building operators to limit that control to prevent overuse and extreme temperature adjustments. Energy savings resulting from the EMS, which cost approximately $500,000 to install, are expected to be 3 to 5 percent of total building utility costs.

Among the challenges of the EMS retrofit, which took more than a year to complete, was that the old system was integrated with the fire-alarm system, which had to remain fully operational. That the building is operated 24 hr a day, seven days a week and houses critical equipment, such as tenants' data centers, made the upgrade even more of a challenge.

New sensors were installed at strategic points on the building's outer core to detect and measure relative humidity and solar load. Previously, outside conditions were measurable only at the top floors, which are unobstructed by shadows from other buildings. The EMS can be used to monitor the sensors and, depending on the weather, allow the engineering staff to either cool or heat the building.

A key component of the EMS are energy-curtailment tools. Building operators are able to limit energy consumption on "quiet days," such as the day prior to a major holiday. While tenant comfort is maintained and vital systems remain fully operational, certain non-vital systems, such as pools and fountains, can be shut down to conserve energy. Likewise, if tenant traffic is especially low, one or more elevators can be shut down. Even the energy used to heat water can be curtailed based on diminished building population.

With the new EMS came replacement variable-frequency drives (VFDs), which allow building operators to regulate electric-motor operation at 70-percent capacity or less, depending on need. This leads to electricity savings of up to 50 percent, based on previous 100-percent capacity usage, which often was unnecessary. The EMS affords the building staff the ability to start, stop, stagger, control, and alarm all fans, pumps, chillers, and other HVAC equipment throughout the building.

The new EMS includes state-of-the-art water treatment, which not only is more efficient and affordable, but safer, as building personnel have less direct contact with water. Remotely accessible smart controllers are interfaced with the EMS.

Cogeration Plant

Bank of America Plaza's cogeneration plant is 4 years old, but still "leading edge" by industry standards. It meets all local, state, and federal codes concerning environmental impact, and its byproducts supplement the heating and cooling of the building. Also, it produces cleaner power and helps with peak shaving. State-of-the-art emissions-control devices, meanwhile, drastically limit the amount of pollutants that escape the building. Nitrogen-oxide, volatile-organic-compound, and carbon-monoxide emissions have been reduced 90 percent, while greenhouse-gas emissions have been reduced by 1,200 tons a year. This would hold true even if the plant were operated only 10 hr a day, 250 days a year.

Upon taking over management of the building, Brookfield put great effort into better utilizing the cogeneration plant.

"We developed a computer energy model that took into consideration current gas prices, utility costs, and building consumption loads," Shane Eaton, the building's assistant chief engineer, said. "This calculated data allows us to run the plant to achieve optimum efficiency at the lowest possible operating cost."

Acceptable Use Policy blog comments powered by Disqus