CIMCO’s ammonia systems travel to outdoor venues for NHL games.
The 31 professional hockey teams in the National Hockey League (NHL) normally play in warm indoor arenas. But since 2003, the NHL has been staging occasional outdoor winter contests, played on temporary ice rinks, in football stadiums and baseball parks across the U.S. and Canada – a feat made possible by CIMCO Refrigeration’s mobile ammonia refrigeration systems.
Toronto-based CIMCO, a division of Toromont Industries Ltd., designed and built two, 53-foot mobile trailers for the NHL that each holds self-contained ammonia refrigeration systems. The systems use an 800-lb charge of ammonia to cool a 40% ethylene glycol mix, which is then pumped through piping sandwiched between a grid of aluminum plates assembled atop the outdoor playing field. A waterproof cover is placed over the plates, and workers spray water on top to form a two-inch-thick sheet of ice.
The refrigeration aspect of the process is virtually identical to that used in standard, permanent ice rink structures, said John Bell, Ontario service manager at CIMCO, who oversees the NHL outdoor series.
The CIMCO system has always used ammonia as a primary refrigerant because of its efficiency, he said.
"They would need a whole row of trailers using some other refrigerant to do what we do with one trailer using an ammonia system,” Bell said.
The NHL launched outdoor games in 2003 with its NHL Heritage Series, and followed that up with the NHL Winter Classic Series. They were such a success that the league added the Stadium Series in 2014, which has included up to four games per year played in various venues around North America.
Although CIMCO began building temporary refrigeration units for the very first outdoor NHL game in 2003 in Edmonton, Alberta, it created the first mobile trailer unit in 2008. The company then built a duplicate trailer system so that the NHL could stage two outdoor games at around the same time. The NHL owns the trailer systems, although CIMCO sets them up and operates them at the outdoor venues, stores them when not in use and maintains them year-round.
The NHL provides the staffing to assemble the rink structure, and also provides a generator to power the refrigeration equipment on site, Bell explained.
The trailers each contain two screw compressors from Frick, which Bell said are rugged enough to withstand the rigors of long over-the-road travel. (See sidebar for a full list of the equipment used on each of the two trailers.)
“It’s not that the trailer has much of an issue when it's sitting at the back of a stadium operating away, but after that it goes on the highway back up to Canada and goes through a few potholes to get here,” he said. “So they have to be pretty rugged duty to manage that.”
Both the trailers and the systems undergo periodic rigorous inspections to ensure they are operating properly, Bell said.
One of the few differences between the trailer-based system and the thousands of ice rink systems CIMCO has installed across Canada and the U.S. is the inclusion of a sump pump for operating in warmer conditions, such as in the Southern U.S. In addition, CIMCO built a heating unit to warm the glycol if the ice gets too cold due to ambient temperatures, which can cause the ice to crack, Bell noted.
“They would need a whole row of trailers using some other refrigerant to do what we do with one trailer using an ammonia system.”
– John Bell, CIMCO
The use of ammonia trailers fits the NHL’s “green” mission to minimize the impact of the league’s activities on the environment, said Lois Stirewalt O’Connor, executive director of the Ammonia Refrigeration Foundation.
“They are trying to keep everything clean and natural, and that’s what natural refrigerants are, so this fits right in,” she said.
On its website (NHL.com), the NHL promotes the use of natural refrigeration technologies, including ammonia and CO2 systems.
“Facilities in need of a replacement of their ice plant may consider natural refrigerants, such as ammonia or CO2,” the website states, noting that both are better for the environment than synthetic refrigerants because of their low GWP and Ozone Depleting Potential (ODP).
The NHL also suggests installing high-efficiency compressors, NEMA (National Electric Manufacturers Association) premium efficiency motors and variable-speed drives on pumps for additional energy savings. In addition, ice surface temperature controls can help maintain desired temperatures and minimize energy use, the website explains.
This article, in expanded form, appeared in the March 2018 issue of Accelerate America.