Controls Help Complex Ascend to 'Energy Star' Status
The tenant base at the property is diversified and includes national companies from such industries as insurance, real estate, legal, telecommunications, and financial institutions. The building team prides itself on the services it provides to the tenant base, while still maintaining the lowest possible operating costs.
Committed To SavingConstructed in 1981, 1982, and 1987 respectively, all three Lakeway buildings went through a major renovation and redevelopment when Equity Office Properties purchased the complex in 1994. In 1999, Equity Office continued its commitment by selecting the Computrols, Inc. CBAS2000 system to upgrade the property's energy management systems.
"This user friendly system gave us the ability to control, expand, operate, and monitor every aspect of the property's operations, while at the same time reducing the number of calls from the building's occupants about their space temperatures," states Randy Spitzkeit, manager of engineering, Equity Office Properties Lakeway Center.
While energy conservation was the primary goal of the project, tenant comfort and safety could not be overlooked. Proper space temperature and relative humidity, as in any controlled setting, was of utmost importance. The energy management system has considerably reduced the energy kW and kWh consumption at all three Lakeway Center buildings.
"Over a 12-month period, we have seen a consumption reduction of more than a million kWh, and there has been a marked increase in tenant comfort. We've seen a 70% reduction in hot/cold calls," Spitzkeit says.
Better BalanceHe attributes the reduction in calls directly to the energy management system. "It is providing a better balance and control of temperatures inside by using not only the space temperatures as a control point, but the outside air temperature to reset chill water temperatures and supply air temperature from air-handler units," he adds.
Even with an increase in cooling degree-days during the summer of 2000 and subsequently the heating degree-days during the winter of 2000, the complex realized a drop in consumption by 1,651,800 kWh over a 12-month period. Additionally, it realized savings of kW by monitoring and managing demand during peak usage periods. The system gained these savings by using auto-tuning proportional integral derivative (PID) control for chiller percent loading, chill water setpoint, static pressure control, and chill water valve operations. Simple if/then logic with an editor; chiller sequencing; normal weekly, overtime, and holiday scheduling; and alarm programming with delays and lockouts are all built into the system and easily programmed to fit every need and requirement at the properties.
The center is also retrofitting tenant areas from a 3-bulb, T-12 fluorescent light fixture, to a 3-bulb T-8 fixture with electronic ballast. Additionally, the parking garage's high-pressure sodium lighting system was retrofitted with an improved metal halide lamp with electronic ballast. Testing of this lamp and fixture have provided a 60%-longer lamp life than the standard metal halide lamp, in addition to providing the appearance of more light with lower wattage and a reduction in the number of fixtures needed throughout the garage. "This was done not only to save energy, but to satisfy a request from our annual tenant survey to increase the light output for security," Spitzkeit says.
Additional energy cost reductions have been realized through systematic maintenance of the mechanical equipment with a computerized preventive maintenance program. "This enables us to consistently meet the maintenance frequency levels for maximum efficiency of all mechanical equipment. Time invested in the training and development of our engineers ensures consistent quality in these preventive maintenance measures along with proper equipment control," adds Spitzkeit.
In addition to saving considerable energy and costs, these efforts paid off when the Equity Office Properties received the EPA Energy Star(r) label for all three buildings. ES