As Renison University College's student body began to grow rapidly, college administrators moved forward with expansion plans. Outlining their objectives for a new building, the college wished to use proven technology to minimize energy consumption and its carbon footprint, while keeping occupants comfortable. The college also required design flexibility to accommodate vertical expansion of the building when its programs and enrollment warranted additional space.
The college's design/build consultants, AEC Developments and WalterFedy Architects and Engineers, contacted Trane to discuss the building's HVAC system design. To accommodate a potential vertical building addition, the option of using rooftop HVAC units was excluded, and the decision was made to move forward with a Trane® EarthWise™ Ice-Enhanced Air-Cooled Chiller Plant.
Shifting electrical consumption to off-peak hours
Trane and WalterFedy worked together to meet the college's objectives of energy savings, extended equipment life cycle, serviceability and space, designing a thermal storage systemfor the new building. Thermal storage allows the college to shift electrical consumption to off-peak night time hoursto avoid the assessment of penalties, and is more efficient at load levelling than a chilled-water-only system. Using thermal storage enabled Renison to reduce the size of its chiller from 90 tons to 52 tons, as well as reduce the amount of duct work, helping to lower equipment and installation costs. In addition, using familiar technology allowed the college to continue using its existing HVAC contractors.
Implementing a high-efficiency system
The Trane EarthWise chiller plant system offers high efficiency, low emissions, sustainable building performance and documentation. The system leverages high-efficiency HVAC equipment and advanced building controls in a complete design concept that optimizes performance. Tapping into the collective capabilities of pre-programmed controls and a preengineered system package reduces risk, complexity and costs.
Generating ice at night for daytime cooling
The system’s CGAM Air-Cooled Scroll Chiller provides high efficiency with low noise, as it generates ice overnight, when energy demand and costs are lowest. Extensively tested to confirm its reliability, the chiller provides factory-installed features to reduce energy consumption and installation time. Two CALMAC® IceBank® energy storage tanks, buried outside the building so as not to take up usable space nor present a visual distraction, store the ice that is then used to cool the building during the day.
Optimizing system operations
Adaptive Control™ algorithms embedded in the factorymounted controller on the Trane CGAM Air-Cooled Chiller help maximize uptime and manage time-of-day scheduling. A Tracer® SC building automation system (BAS) is used to manage chiller sequencing and load sensing for optimum control on site and is Web-enabled to provide mobile access.
Improving indoor air quality
Designed to encourage energy conservation, three high efficiency Trane Performance Climate Changer™ air handlers with heat recovery wheels, installed in the basement, deliver low-temperature air throughout the building. Moving less air, the low-flow air handlers require less duct work, resulting in quieter operation. The colder air also lowers building dew point, improving humidity control and indoor air quality.
Renison University College, in partnership with WalterFedy and Trane, implemented a building cooling system with thermal storage. Early results show electrical demand and consumption savings to be greater than predicted, with 97 percent of the cooling system electricity use shifted to off-peak hours and a peak demand reduction of 88.6 kW. Peak energy savings is predicted at $12,000 annually. Based on the energy savings, Renison University College also achieved a significant utility rebate from Waterloo North Hydro.
“The system has been running without fault and with minimum oversight. Occupants have commented on the consistent climate, and the energy savings have been realized,” said Jim Robson, manager of plant operations/facilities, Renison University College. “Renison University College is committed to following environmentally sound practices, and as such, the Facility Manager has a duty to be a responsible steward of our resources and to choose processes or equipment to minimize the College’s impact on the environment. Our Trane ice system best meets those criteria."