March 22, 2012
Unusually high temperatures this week likely won't change the cooling schedule, but if the trend continues it may prompt an early start.
Typically, April and October are "shoulder seasons" as they represent the transitional months of the changing seasons. Although it would seem intuitive to start air-conditioning campus building with our record setting heat wave, the forecast also indicates some sub-zero evenings. This large variation in temperature presents the challenge of the shoulder season.
To switch to the cooling system takes a few weeks. Cooling coils need to be filled with chilled water for each of the 90 buildings on campus. Once there is a commitment to cooling, if the weather turns cold again, this time consuming and expensive process may need to be reversed. If Southwestern Ontario returns to normal temperatures in April and May, it could be very cool in our buildings. That said, if temperatures remain above average for an extended period of time, the cooling season may begin in early April.
“We need to balance the needs of the customer as well as protect the chilling equipment,” says Rod Crichton, Power Plant Manager. “We only want to load the chilled water lines once a season, otherwise we are wasting time and resources - that is the juggling act that we perform each shoulder season.”
Another challenge comes as evening temperatures dip below freezing. Coils can be damaged if ice develops and expands, perforating the line. As the ice melts, the chilled water will pour out of the coils through the cracks, leading to downtime and repair.
“There are staff, faculty, and researchers working in support of the University’s mission and we will have students writing exams,” says Crichton. “It’s important we provide a comfortable environment for everyone.”Facilities Management understands the need to accommodate building occupants and maintain steady climate levels. The target for an average office and/or classroom is set between 20 - 25C throughout the year.