Changeover to Air Conditioning in the Works

  Claude Rioual descends into a manhole while Dan Benvenuto secures safety equipment.

The annual campus-wide operation that results in the conversion from winter heat to summer air conditioning for most Trinity buildings has begun. Assistant Plant Engineer Jim Egan and his two-man crew, Energy Plant Specialist Claude Rioual and HVAC Technician Dan Benvenuto, started the approximately two-week process on Thursday, April 29, by shutting down the boilers that keep the College’s hot water system at 210 degrees during the winter. That water, which runs through insulated, underground pipes, must be allowed to cool naturally to roughly 80 degrees before it can be fed into the chiller system. That process then cools the water to 40 degrees, which is used to produce air conditioning.

After more than nine years at Trinity, Egan is well aware that most people on campus have no idea of the complexity of the changeover process. The initial challenge is to decide on a date to shut down the boilers. “While faculty and staff are, for the most part, only in their offices during the day, our students live here 24 hours a day,” says Egan. “It can still get pretty cold at night, even when we’re having warm afternoons. We try to wait until we think the cold weather is really behind us, but it’s always a gamble.” The decision to start the conversion is made based on current forecasts combined with average temperatures over the last five years.

Once the boilers are turned off, meaning that the water in the two-pipe system is no longer being heated, Egan and his crew begin the arduous process of redirecting the flow from the boilers into the chillers. The College has three main boilers in the Central Energy Plant; two are in use while one is always on standby. They are fed through pipes that run virtually under the entire campus. The water is manually redirected through an intricate series of valves and shut-offs, which are accessed through manholes around campus or are located in the basements of buildings.

In addition to redirecting the water flow via the valve system, each building’s air-handler and coil system must be thoroughly tested before the air conditioning system can be activated. The crew does this while they are waiting for the water to cool down. Any necessary repairs are made before the air conditioning is turned on, thereby avoiding costly problems once the system is brought on line.

“This isn’t like your home heating and cooling system,” explains Egan. “We do this twice a year—in the spring and in the fall. Once we shut down the boilers, they’re down; same with the chillers. That’s why we try to make sure that everything is operating properly before we activate the system each time. We try to make this as painless as possible.”

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