Innovative arena cooling solution
- by Simon Blake
There’s always more than one way to do things. When the City of Belleville, Ont. decided to upgrade the cooling system at its Yardmen Arena complex, officials were looking for a solution that would meet the building’s comfort cooling needs but also substantially reduce operating costs.
Home to the Ontario Hockey League Belleville Bulls, the arena was built in 1978 with mechanical systems that were state of the art at the time. This included a 215-ton R-11 centrifugal chiller that was substantially oversized to allow for a future expansion that never occurred, reported the City of Belleville’s Peter Lyng. “It ran very inefficiently; we could never load it up properly.”
The phaseout of R-11, a chlorofluorocarbon (CFC) refrigerant with high ozone layer damaging potential, added further impetus for an upgrade. “When the Ontario and Canadian governments decided that R-11 was really bad and we had to get rid of it, it was a good time to look for a smarter solution for the building.”
The city put out a request for proposals (RFP) for a “turnkey system” to replace the existing system, asking for equipment that would be environmentally friendly and more efficient to operate.
The city received eight proposals, seven of which included similar systems to the existing setup, but typically with two 100-ton chillers that would cycle back and forth depending on need. That may have been somewhat more efficient, but it didn’t make the significant gain the city was looking for.
Officials wanted a solution that would substantially reduce operating costs at the Yardmen Arena.
A new/old idea
Stantec Engineering with design-build partners Trane Co. and George A. Kelson Mechanical proposed a significantly different solution that incorporated a Calmac ice storage system with Trane Tracer chilled water system plant and ice controls.
“The Kelson team came back with a 120-ton air cooled chiller and the Calmac tanks. That intrigued me right off the bat,” said Lyng. It turned out as the most efficient and lowest cost system – “a double win for me” – he added.
Stantec’s Kashyap Desai designed the system, working with Calmac to size the ice storage tanks. The new system was designed to provide 200 tons of cooling.
Trane supplied the chiller, variable speed drives for the pumps and control system.
Desai has been designing high performance cooling systems for 30 years. When he looked at the Yardmen Arena complex and how it is used along with the variations in cooling load, it seemed like an ideal candidate for ice storage, particularly with the new time-of-use electricity rates.
It is not used every day and seldom requires air conditioning for 24 hours. Typically peak loads only occur for brief periods – from two to four hours – during a hockey game or concert.
“The question is, how much ice have you been able to make during a 10-hour period at night, because that’s when your off-peak hydro rates apply?” noted Desai. In the Yardmen Arena, that was more than enough to cool the building all day.
Typically a thermal storage system would have a higher capital cost than a conventional chiller system. However, Desai did the calculations and estimated the cost at $100,000 less.
The cost savings allowed the city to add air conditioning to the dressing rooms, which weren’t previously cooled, and a Trane Tracer building automation system which controls the entire building from a central console.
Because the technology was so unfamiliar, Desai took city and Kelson staff to Minnesota to look at ice storage installations, primarily in schools. “Because it was a design build, I wanted to ensure that Kelson was up to speed. If any one of these players did not understand properly or made a small mistake, the risk (of the system not working properly) would be just too high. I was trying to mitigate risk on everything so that when we started up and commissioned the system there were no problems,” remarked Desai.
Lead hand Scott Stobbart adjusts freeze time of the tanks. (All photos by Murnaghan Photo)
Ice storage technology
Ice storage cooling technology is not new. Calmac has done around 4,000 installations over the years, reported company CEO and engineer Mark MacCracken.
In fact the industry saw considerable growth in the 80s and early 90s as the electrical utilities began facing power shortages. It receded somewhat as the utilities were split into generating and delivery companies.
However, with the onset of energy efficient buildings along with lower off-peak electricity rates, ice storage systems are enjoying a resurgence. The building operator can run the chiller at night to take advantage of lower off-peak electricity rates, freezing the ice storage tanks, and then enjoy “free cooling” when the rates are at their highest during the daytime.
“Mechanically, there is very little difference between an ice storage system and a mechanical system,” added MacCracken. “In a conventional system you have a chiller that is cooling water where as in our system you have a chiller that is cooling an antifreeze solution and now the chiller runs at night as opposed to during the day….it’s a slightly different fluid and different controls, but the plumbing is a supply and a return just like on a chiller.”
Finding space for the tanks wasn’t difficult either. The original mechanical rooms were designed, again with expansion in mind, for a larger system, said Lyng. “So I had tons of room indoors for these tanks.” And the new chiller is roof-mounted. “Where I lost space by putting in the tanks, I gained by removing the chiller.”
For Geo Kelson, it was the first ice storage project the company had done in eastern Ontario, reported district manager Rick McGurn. Although more complex than a straight chiller changeout, the project was straightforward, he reported.
The Yardmen arena was in full operation during the changeout over the winter of 2009-2010. The city worked with Kelson Mechanical to ensure as little impact as possible to day-to-day operations.