A task force at the City of Mississauga has slashed the electricity consumption of the ice-making equipment at its Iceland Arena by 22 per cent during winter and shoulder season operations, staff say. The improvement in energy efficiency for that timeframe represents a weekly 136-kilowatt drop in electrical demand, which works out to savings of $38,000 per year.
The task force achieved these results at Iceland Arena while maintaining the quality of ice required by different user groups, staff say. The municipal rink runs year-round, hosting everything from fun and figure skates to competitive and sledge hockey. With three pads measuring 185 feet by 85 feet and one Olympic-sized pad measuring 185 feet by 100 feet, the facility serves seven vendors and roughly 950,000 visitors annually.
The success of the pilot project at Iceland Arena has paved the way for the energy efficiency program to be rolled out to the rest of the City of Mississauga’s 12 rinks.
Benchmarking activities pinpointed ice arenas, which are known power hogs among municipal facilities, as prime candidates for energy efficiency improvements, said Daniela Paraschiv, manager of energy management, City of Mississauga.
“Our team continuously monitors energy consumption in City-owned facilities, identifies top consumers and compares their performance with similar type facilities within the City of Mississauga and with other facilities in other municipalities,” Paraschiv explained.
The energy management team formed a task force to tackle energy efficiency at municipal ice arenas with the goal of finding low- or no-cost strategies, such as changes in standards operating procedures, with the potential to deliver outsized savings.
After researching best practices recommended by industry groups including ASHRAE, Natural Resources Canada (CanmetENERGY) and the Ontario Recreational Facilities Association, the task force moved to install meters on the refrigeration equipment at Iceland Arena to track real-time energy consumption. It was also important to control for unintended consequences as the team experimented with changes to operating procedures, said Sumeet Jhingan, energy management coordinator, City of Mississauga.
The task force experimented with different ice surface and hot water resurfacing temperatures in an effort to reduce loads on the equipment and used CIMCO 5000E controls to give the equipment time to rev up and down to avoid extreme ups and downs in usage.
“It’s like taking a car and essentially pressing on the accelerator right to the max and then going straight off from the stop sign to your point of destination, and then every time you’re coming to a stop you’re hitting the brakes,” said Jhingan. “It’s a very inefficient way of running things, so we wanted to somehow ease into and control the equipment better.”
In between user groups, the ice surface is shaved down and flooded by Zambonis, which happens 16 times per pad per day. The water used to resurface the ice afterward is the main source of demand on the compressors, observed Michael Blazenko, supervisor of operations at Iceland Arena.
The temperature of the water has to be cooled from 150 to 160 degrees Fahrenheit to 20 to 22 degrees Fahrenheit. The difficulty in tinkering with the temperature of the water used to resurface the ice, said Blazenko, is that if the water is too cold, it creates shale, or ice that is prone to breaking off in large chunks. The supervisor of operations said that he had been game to pursue energy savings, but he added that they couldn’t come at the expense of ice quality.
However, there is no industry-wide standard for how to measure ice quality, other than thickness, noted Jhingan. The staff at Iceland Arena check and chart 25 points of interest on each pad twice a week, with a targeted thickness of around 1.5 inches.
During the eight-week pilot project, Blazenko and Jhingan met twice per week to set the schedule for the rink, which accounted for the different requirements of different user groups. Figure skating, where users are planting toe picks into the pad, demands softer, warmer ice, while hockey games, where users are traveling across the pad in crossovers, demand harder, cooler ice, said Blazenko by way of example. The control system has three temperature set points, which are programmed for game and recreational uses as well as for when the pads are unoccupied.
Staff at the Iceland Arena only received one complaint over the course of the eight-week pilot project, Blazenko reported. In that case, the water was taking too long to freeze in between user groups because the ice was too warm, he said.
“Because of this complaint, my team and I knocked down our infrared reading by a 0.5 degree Fahrenheit (from 27 degrees Fahrenheit to 26.5 degrees Fahrenheit) and that ended up being our sweet spot,” Blazenko said.
Over the course of the pilot project, the data captured by the meters installed on the refrigeration equipment showed consumption flattening out from spikes in week one, as the compressors switched on and off, into a straight line in week eight, said Jhingan. Before, four out of five compressors would run continuously, and the fifth compressor would run afternoons, said Blazenko. Now, two out of five compressors run continuously, and the third compressor runs as needed, reducing the wear and tear on the equipment.
Following Iceland Arena’s success, the Hershey Centre volunteered to be the next City of Mississauga rink to participate in the energy efficiency program. But the optimization of its operations will have to be unique to its controls, equipment and facility, said Jhingan.
The main bowl in the high-profile Hershey Centre is used by Figure Skate Canada and junior Ontario Hockey League team the Mississauga Steelheads, so the search for electricity savings will be limited to the facility’s three community rinks, he added.
The City of Mississauga plans to roll out the program to the rest of its ice rinks incrementally, as resources permit, said Paraschiv.
Michelle Ervin is the editor of Canadian Facility Management & Design.