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Unseasonable temperatures pose a challenge to campus heating and cooling systems

With winter temperatures now dipping low on the thermometer, the campus community is reminded that Facility Services staff has completed the semi-annual system switch from summer air conditioning to cold-weather heating.

Susan Mark, executive director of Facility Services, says maintenance staff spent several weeks preparing equipment at the Energy Conversion Centre, the Central Refrigeration Plant and buildings across campus, and now that the change is in place there is no going back until spring.

“We want to prepare people ahead of time so they understand that if we have an early winter thaw like last year, temperatures may be high in some campus buildings,” Mark says. “Making the switch from heating to cooling and vice-versa with the University’s centralized system takes a great deal of planning and time. It’s not the same as flipping a switch in your house and turning on the air conditioning one day and heating the next.”

She says that while the current HVAC system is at a disadvantage in terms of easy switch-over, it does offer the following advantages:

  • The central cooling system has 4,800 tons of installed capacity. If each building were cooled individually, the installed capacity would rise to 6,200 tons. The central system allows for diversity, thus reducing the overall required installed load.
  • It allows for the purchase of energy at reduced rates due to the larger volume.
  • The low carbon footprint of the heating and cooling system reduces production of greenhouse gases, thus reducing global warming.
  • Less space is required in individual buildings to house mechanical equipment dedicated to cooling, thus allowing increased space for academic programs. It also reduces maintenance costs.

Mark says 2012’s unseasonably warm spring, which saw record daytime high temperatures of more than 20C degrees in March, caused uncomfortably warm temperatures in some buildings. The dilemma, she says, is that based on historical data, building heat is often still required during the months of March and April. The same conundrum presented itself this fall when unusually warm fall temperatures occurred after air conditioning was shut down for the season.

“It’s a challenge to manage building temperatures during what we call ‘shoulder season,’” Mark says. “We can’t take the chance of our buildings being cold during these times either, so we have to err on the side of caution and schedule our changeovers based on what we know about historical seasonal temperatures. Unfortunately, we’ve had some very unusual temperatures over the past few years and this adds to the challenge.”

There is, however, a bright spot on the temperature horizon. Facility Services is currently completing an infrastructure upgrade to the chilled water system on campus at a cost of $4.5 million dollars over the next several years. It will increase system efficiencies, provide significant energy savings, and optimize chilled water distribution more effectively in response to an increase in demand.

In the meantime, Mark promises that in the event of a mid-winter thaw, maintenance staff will be optimizing damper settings in buildings to take advantage of cooler air in the evening to assist in reducing inside temperatures, and suggests that if necessary, temperatures can be moderated by taking the following steps:

  • Be sure that individual room thermostats are not set on high settings;
  • Turn off lights when leaving a room;
  • Leave doors open to improve air circulation.
  • Close any available room blinds;
  • Unplug any appliances not in use.
  • Turn off all computers and printers at the end of the day.

Mark also says that Facility Services carefully reviews the heating and cooling switch schedule on a yearly basis and will adjust it accordingly depending on changes to regional temperature norms.