Energy-saving measures
May 1, 2010 12:00 AM
Osseo (Minn.) Area Public Schools is embarking on a program that will improve energy efficiency in its facilities. With about 21,000 students and 27 buildings that total nearly 3,700,000 square feet of building area, the school district seeks to significantly reduce energy costs. The program the district is adopting consists of re-commissioning all facilities, incorporating preventive-maintenance software, conducting a 10-year mechanical and electrical systems audit, monitoring monthly energy summary reporting, and carrying out recommended energy-saving techniques and capital investments.
To begin with, the re-commissioning portion of the program is a five-year plan that includes Energy Star benchmarking (through the U.S. Environmental Protection Agency) to initially compare each building's energy use with standards. All energy management and control systems (EMCS) are evaluated for air-handling unit scheduling (relative to staggered scheduling, demand spikes, start-up/shut-down efficiency), lights scheduling, variable-air-volume sequences, air-handling unit sequences (relative to dampers and outside air), pumping sequences, energy-wheel operation, chiller and boiler sequences, graphics display upgrades, critical alarms, humidity sensing, EMCS override policies, energy-saving measures, auto-commissioning, continuous commissioning and verification of balancing reports.
Second, incorporating preventive-maintenance software consists of entering equipment data. The district recently purchased a new preventive-maintenance software package that will be synchronized with the plan.
Third, the 10-year mechanical and electrical facility analysis will include all systems to determine improvements and upgrades.
Fourth, monthly energy summary reports will be recorded for each building. The data will be collected on a monthly basis to compare new data with the previous year.
Finally, the top priorities include Energy Star benchmarking, air-handling unit scheduling, lighting scheduling, variable-air-volume boxes sequencing, outdoor-air AHU sequencing, pumping sequencing, boiler sequencing, verifying balancing reports, humidity sensor installation and EMCS upgrades.
The first phase of work includes six schools totaling about 745,000 square feet. By targeting "low hanging fruit" programs and capital investments, the district will immediately realize close to a 15 percent reduction in annual energy costs. With the assistance of energy rebates from the local utility, the cost payback is estimated at two years. With the same approach, the district will upgrade its remaining facilities to realize substantial energy savings immediately. The second phase of work will include additional capital investments over 10 years.
