What made this such a complex job was the unique lay out of the building. First Canadian Place consists of four chilled water systems plants and a total of nine chillers over the 72-floor building.
A total 1,800 tons of cooling capacity is utilized for each section of the tower in plants B, C or D. Some 2,000 tons of cooling capacity was required for the podium at plant A and a total of 2,000 tons of cooling capacity was required on the top floors in plant D.
The 72-floor building also added complexity to the mechanical systems serving the tenant space. The hydraulic pressures resulted in the building being mechanically divided into four systems.
Plant A serves the lowest levels of the building, from B-3 to parts of the 3rd floor, including office tenant space, retail space, parking, and restaurants. Plant B serves the low-rise segment of the tower, from the 3rd floor to the 25th floor, including office tenant space. While plant C serves the mid-rise segment of the tower, from the 26th floor to the 49th floor, including office space.
Originally seven chillers were located in the B-3 mechanical room -- chillers A1, A2, A3, B1, B2, C1 and C2. These chillers are configured into a primary loop. The secondary loop is divided into the three segments of the building, according to the pressures for which they were designed.
Plant A is designed to have a maximum operating pressure of 150psi, being the lowest of the pressures in the plant. Plant B is designed to have a maximum operating pressure of 250psi, while plant C is designed to have a maximum operating pressure of 350psi. The chillers for plant D (D1 and D2) were located on the 73rd floor.
First Canadian Place also recovers the heat produced from the chilled water, during the months when both cooling and heating are required. This water is used to preheat or reheat the air. During the summer there are three heating loads in the building, all of which are served by this heat recovery system including; the podium, 3rd floor of the Bank of Montreal, the 68th floor, and domestic hot water for plant D. Plant A was designed for simultaneous heating and cooling similarly in Plant D.
This further added to the complexity of the project. As the chilled water systems operate year round, the engineering and maintenance teams had to ensure that the plants were running continuously and that service was never disrupted, said Charlie DiPietro, account executive, at Trane in Toronto.
Trane, which Aldcroft chose because of the reputation of its heat recovery chilled water system, as well as his faith in the refrigerant used, was responsible to supply and land the chillers on the pad ready to be piped. It was also responsible for start-up and commissioning.
Through extensive planning and consultation, Aldcroft, the mechanical experts and the team at Trane, decided that a retrofit was the right way to go, but that a total of 10 chillers would be used to replace the existing nine.
“We had no choice. Those chillers were over 30 years old by the time we had gotten them out. They had to be replaced along with a lot of other mechanical equipment in the building,” Aldcroft said.
“We decided the best way to go was to replace all the equipment and so we started on that project in late 2006 or early 2007 and developed a plan that would be replacing the nine original chillers with 10 new ones.”
The new chilled water systems included two 1,200-ton heat recovery units, two 600-ton heat recovery, and two 1200-ton cooling chillers for a total of 6,000 tons. Additionally, the 73rd floor mechanical room chilled water system plant D saw four chillers installed including two 500-ton chillers and two-500 ton chillers with heat recovery to be installed for a total of 2,000 tons of chillers.
The reconfigured system means massive savings for the company, Aldcroft said.
“The new chillers are 40 per cent more efficient than the original chillers, so we have been able, on an energy basis, to save 40 per cent of all the cooling energy in the building over the summers and winters because we use them for both heating and cooling,” he said. “That saving is much greater for us than it is for most people because we run them summer and winter.”
If the planning and designing of the building was difficult, the actual retrofitting and implementation of the project was another challenge.
With the biggest chiller weighing in at a massive 65,000 pounds and measuring 24 feet long by 18 feet high, and another one tipping the scales at 20,000 pounds, a huge concern for Trane was getting them to the right places.
“The biggest challenge from the whole project was, once we got into the implementation stage, was physically landing the chillers into the building,” said Phil Owens, Ontario Area Manager for Trane. “This took a lot of planning. You couldn’t just show up there with chiller pieces and start putting them in. There was extensive planning.”
To ensure that the massive project did not see any unforeseen problems, Aldcroft along with a carpenter and a construction manager, constructed a wooden mock up of the largest component to be sure it would fit into the elevator.
Modifications to the elevator which would be used to hoist the equipment to the upper regions of the building were also done.
“It was a massive job. One of the interesting aspects of it was that there was some doubt as to whether the machines would actually fit in the elevator,” Aldcroft recalled.
The teams were also required to work mostly at nights and weekends to ensure that the tenants and the daily operations of the building were not disrupted.
The first phase of the project is winding down, and now a second phase -- which should take about six months -- will begin shortly. This includes replacing all the pumps associated with those chilled water systems.
Still all concerned look back at the project, which was some four years in the making, as a successful undertaking.
“It was a very complicated job. There were a lot of trades that had to be co-ordinated and managed and organized to be able to get this done. I could not be happier with the satisfaction that the customer had of the co-operation of the team on something like this,” said Owens.
“This could have gone sideways and could have cost him a lot of money if it did go sideways, but it was managed very well.”