Committed to creating a sustainable campus, Delta College moved forward with plans for an energy-saving cooling system. Pleased with previous project performance and the reliability of Trane equipment, Delta College selected Trane and CALMAC to partner with them on the implementation of thermal energy storage on their campus.
The campus’ thermal energy system includes Trane CenTraVac centrifugal chillers, which offer the industry’s highest full- and part-load efficiency and a robust design to ensure reliability. Using the chillers’ free cooling option provides up to 45 percent of the normal chiller capacity, without running the compressor, for significant cost savings. A Trane absorption chiller works with the centrifugal chillers, using heat to drive the refrigeration cycle and producing chilled water, while consuming only a small amount of electricity to run the pumps. The chillers make ice at night when energy is in lower demand and less expensive. The ice is stored in CALMAC Ice Bank thermal energy storage tanks, and then used to cool buildings during the day.
Thermal energy storage systems were installed on the Delta College campus on three occasions as the school expanded its footprint to accommodate growing enrollment. The first installation, which included forty-five CALMAC Ice Bank thermal energy storage tanks and two 800-ton Trane CenTraVac chillers, provided 100 percent of the school’s cooling. As needs grew, the system was expanded to include 200 kW of energy storage, and due to a greater than anticipated cooling load, the thermal storage system piping was reconfigured to allow the college to run the chiller plant while it was melting ice. In the third instance, the chiller plant was converted from a secondary system to a full ice storage system to cool the entire campus with ice during the day. The expansion included the addition of two 800-ton Trane CenTraVac chillers, which can operate with low global warming potential refrigerants. The chillers run in sequence for optimal efficiency, and 500 kW of energy storage. With a total of eighty-one CALMAC Ice Bank thermal energy storage tanks, the college now has 1.6 MW of energy storage, providing 13,500 ton hours of cooling throughout the campus.
Facility managers use a Trane Tracer Ensemble, a web-based building management system to operate the chiller plant and portions of the airside and waterside systems. Accessible from most PCs, tablets, and smart phones, Tracer Ensemble provides immediate access to systems from virtually any location to maintain a comfortable learning environment. Operators use Tracer Ensemble to monitor system performance, change setpoints, establish scheduling, and manage alarms, as well as analyze system data to ensure optimal operation.
Central cooling system upgrades, implemented by Trane and CALMAC at Delta College, have increased capacity to accommodate growing campus needs, while reducing electric and gas consumption, as well as the facility’s overall carbon footprint. The improvements have saved over $100,000 per year in energy costs, reduced electric demand by 1.5 MW during peak demand, and eliminated over 2000 metric tons of CO2 emissions produced by the facility, helping to meet sustainability objectives. In addition, Delta College’s Health Professions Building achieved LEED Gold Certification, becoming one of only three buildings in the region to earn this level of certification.
“I was here for the first implementation of the energy storage system and have been able to see success the program has had along the way,” said Larry Ramseyer, Director of Facilities at Delta College. “From installation to learning and running the tanks, the entire experience with CALMAC’s technology has been smooth. With the controls, I can easily run the energy storage system from my smartphone. The ice tanks provide reliable, controlled cooling throughout the campus to create a comfortable environment for students and staff.”
