Refrigeration – A Canadian assist at the Olympics
Refrigeration – Canadians and ice seem to go hand-in-hand, so it may not come as a big surprise that the Olympic sliding centre, where the bobsleigh, luge and skeleton competitions are taking place during the Winter Games in Sochi, Russia, have a connection to our country.
Drawing from an international community of experts in their field, Calgary-based ISC/IBG Group member companies have designed the tracks for the past six Olympic Games. The Sanki Sliding Center, located just under an hour outside of Sochi, in Rzhanaya Polyana, became the company’s sixth consecutive Olympic track when the Games opened on February 7.
Terry Gudzowsky, the firm’s president, led the group that worked on the Sochi 2014 Sanki Sliding Center project, and was active from the preconstruction stages onward, watching as the site went from a rugged outcropping in the mountains to a sliding facility that will attract athletes from all over the world, both during the Olympic Games and for years to come following the closing ceremonies.
“My first trip there, I was sent by the International Bobsleigh Federation the week before the Olympic Games in Torino,” says Gudzowsky. “That was a kind of reconnaissance mission to see where a track could possibly be built.”
What he found during that 2006 trip was a beautiful mountain region that was home to a ski resort a little over a half-hour away from the resort town of Sochi.
“It is a very mountainous area, a couple thousand metres high,” he says. “That’s good in terms of weather, but in terms of terrain, it is very steep. It is very rugged; and it was very difficult to find a location. We found a location partly down a ski hill.”
An ideal spot for a track, he says, is an area that will accommodate a build site that’s around a kilometre long, and about a half-kilometre wide, with a slope that will generate speeds that easily exceed 100 km/h. “That doesn’t really exist, so you have to fit the design into the area that you have.”
Once an area is found that’s close to ideal, the details are sent to the international sliding federations for approval, after which the real site preparation work begins.
“You want to follow the lay of the land as much as possible,” explains Gudzowsky. “For one, it’s cheaper, but it is also aesthetically better for the athletes to follow the lines, and it doesn’t disturb the slope. What you hope to do is leave as much of the forest in there as possible because it helps with the slope stability, and you create little microclimates that help keep a cooling effect on the track.”
Mapping the track
Before a track is built, a number of possible track layouts will be modelled on a computer.
“We do a contour map of the land at about 0.5 metre intervals,” says Gudzowsky. “What that allows us to do is create an initial centre line.”
Using that centre line and computer modelling software, designers can calculate approximate speeds, velocities and gravitational forces for each of the sports that will use the track.
“Once we have the track design, then we get into more complicated drawings of the curves and so forth,” explains Gudzowsky.
That leaves the company with a cross section of the complete track, in three dimensions.
“Once you have the track design, then you can start to design the refrigeration system, because the refrigeration system is, of course, in the track.”
Dealing with micro-climates
Building something that will be almost two kilometres long that drops almost 150 metres along its path creates challenges for the mechanical systems designers, and for the crews that will take care of the refrigeration system and the ice once the facility is built.
The drop in elevation required the ammonia ice plant to be robust enough to ensure that ice could be made all the way to the top of the 1,800-metre track, and the elevation changes create different climactic environments that affect the ice in sections of the run.
Not only that, but the system needs to be ready for any weather conditions that could be experienced during competition.
“The track is made so that if you really had to, you could refrigerate it at as much as 20°C,” reports Gudzowsky. “That requires a lot of refrigerating power.”
The ammonia ice plant at the centre is built to provide up to 3,730 kW of refrigeration – more than 1,000 tons.
“Typically it doesn’t get that warm, but we are in an area of the world where it might,” he says. “This year they have snow, so that will cut down on the operating costs for refrigeration.”
Although the track will be seamless ice on its surface, temperature changes can cause expansion and contraction in the concrete, steel and pipe used in the walls of the track, so expansion joints are built in.
“The track isn’t one continuous length of concrete and pipe,” says Gudzowsky. “On the outside, you have a layer of ice, then you have a layer of concrete, and then you have two layers of rebar, and then refrigeration pipes in there, and another two layers of rebar behind that, and more concrete and steel mesh, so you have a layered system all the way down the track, with around 82 kilometres of pipe inside the track, and about 6.8 kilometres of long distance connector pipes for evaporators, valve stations, and so forth.”
Keeping the ice nice
Temperature and sun exposure affect ice, and along an 1,800-metre track, the conditions can vary from section to section. As such, designers build in shading systems that can be adjusted for each section or zone, to help keep the conditions as consistent as possible all along the run.
“When you make the ice on the track, you want to keep a uniform thickness,” says Gudzowsky. “Once the concrete is cold, icemakers start spritzing it with hoses – which infers, of course, that you have a water supply system all the way up the track that is workable in all temperatures right down to -30°C. Spraying it on doesn’t give you a smooth surface, so the track workers use scrapers to scrape it smooth all the way down, and that’s really an art.”
About the Track
• 3,730 kW ammonia system.
• 82 kilometres of steel pipe.
• 7,400 square metres of ice.
• Elevation from the top of the track to the bottom, where the refrigeration system is, is 132 metres.
Full Length of Track: 1,800 metres
Competitive Length of Track:
• Bobsleigh: 1,500 m
• Skeleton: 1,500 m
• Men’s Luge: 1,475 m
• Women’s Luge: 1,384 m
Turns: 18 total, 17 for competition
Estimated Average Grade: 9.3%
Calculated Speed Ranges:
• Bobsleigh: 125 to 135 km/h
• Skeleton: approximately 125 km/h
• Luge: 128 to 136 km/h
By Adam Freill