High school earns an ‘A' for energy efficiency with new BAS
Buffalo Grove High School, in Buffalo Grove, IL, has been transformed from an "energy hog" to a model of energy efficiency and savings. Students are learning in a comfortable and safe environment while taxpayers reap the savings following the installation of a new BAS. The improvements are the result of a district-wide system upgrade undertaken by the Township High School District 214.
Located approximately 30 miles northwest of Chicago, District 214 is the second largest high school district in Illinois, serving more than 250,000 residents in several communities. Built in 1973, Buffalo Grove is one of six comprehensive high schools in the district and has an enrollment of more than 2,100 students.
THREE SPECIFIC GOALSTo resolve energy management and other issues at Buffalo Grove and all its schools, the district partnered with ITG Solutions Inc., of Homewood, IL, the local TAC representative. The district had three specific objectives: upgrade all temperature control systems, both retro-fit and new construction; add access control at critical locations; and provide multiple operator workstations on the school district's existing LAN.
ITG recommended a Tour Andover Controls BAS to meet the district's needs. This solution upgraded the district's aging facilities to meet present building control requirements and energy management initiatives while remaining within a tight budget.
The first facility renovated was Buffalo Grove, the school that was known as an energy hog. In the initial installation, multizone roof-top HVAC units were removed and replaced with McQuay International rooftop VAV air handlers and VAV boxes. Construction of the cen-tral chiller plant, which includes a Baltimore Aircoil Company (BAC) ice storage system and hot water heating plant, was done over two summers.
Doug Smith, building and grounds supervisor at Buffalo Grove, monitors the entire building from a single workstation in his office outside the school's central chiller plant. He can adjust individual classroom temperatures, modify the school bell schedule, acknowledge alarms, and troubleshoot potential problems with the RTUs, boilers, classroom unit ventilators, VAV units, pumps, fans, etc., with just the click of the mouse. Smith's workstation is connected via the district's LAN to a central workstation and file server in the district's central maintenance office, where all alarms at Buffalo Grove, or any district school, are monitored simultaneously.
Relying on the new BAS, Smith does not spend his day running around the high school addressing complaints about the tempera-ture in the building. Even on a typical 0°F winter day, his eight boilers and two circulating pumps are humming along under peak conditions without a glitch and still at only 65% capacity.
Occupancy sensors installed in each classroom at Buffalo Grove integrate lighting and VAV control. When a classroom becomes unoccupied, the lights shut off after a predetermined time period, heating/cooling returns to its unoccupied setpoint, and VAV dampers are positioned to minimum setting.
SUMMER SCHOOL SAVINGSAdditional energy savings are realized during the summer school session according to Smith. Because the district only uses about one-fifth of the school building for summer classes, he can cut energy by turning on only the rooftop units needed in this one area.
Buffalo Grove also uses an ice storage system to produce chilled water for air conditioning. This system was chosen for its potential to reduce the impact of demand charges through utilization of lower off-peak energy rates. During eight months out of the year, the system makes ice at night when electricity costs are the lowest per kWh and there are no demand charges. The following day, the system melts the ice to make chilled water, in lieu of running chillers when electricity costs are the highest per kWh and demand charges are in effect.
According to Seymour Schwartz, the district's director of buildings and grounds, the ice system is probably the school's greatest money-saving device. He notes that the air conditioning at Buffalo Grove runs approximately $10,000 less per month than air conditioning at a school in the district without an ice system.
Energy savings since the installation of the new BAS have been impressive. According to Schwartz, electricity costs at the school went from an average annual cost of $400,000 to $318,000 in the first year, despite the fact that after the renovation, lighting levels dou-bled and fresh air requirements tripled.
"Utility money is wasted money," comments Schwartz. "We have a $2.5 million gas and electricity budget district wide. Our goal is to reduce this amount without affecting comfort and health."
The effective use of the BAS has played a major part in meeting this goal. Building ice and shutting off chillers, turning equipment off to reduce demand, lowering lighting levels, adjusting occupancy schedules, and modifying temperature setpoints are just some of the ways the control and monitoring capabilities of the TAC BAS have played an important role in this effort.