August 16, 2024

Uy Pham

11th Grade

Fountain Valley High School

Ice hockey games, figure skating competitions, and speed skating races. An entertaining ice skating session with your friends. What do all these activities have in common? They all require ice rinks. The factors that maintain the temperature and structure of ice rinks are essential to ensuring that all ice activities, from recreational activities to professional sporting events, can be completed in a standardized, safe, and consistent manner — no matter the location of the ice rink. 

When skating originated in Finland and after the Dutch invented ice skates, ice rinks were only natural in areas of frozen bodies of water. The first organized indoor game took place in Montreal, where an indoor hockey game took place. On the other hand, recreational skating was introduced by the British to North America in the 1840s, later expanding with the influence of the Dutch and French. Eventually, the construction of ice hockey rinks expanded across Canada and other parts of North America. 

Now, ice rinks use similar technology as used in your house’s refrigerators and air conditioners. Ice rinks are artificially frozen, unlike the natural ice rinks in frozen rivers and lakes common in the early origins of this recreational activity. The first artificially frozen rink was installed in Madison Square Garden in New York, and as refrigeration techniques improved, ice rinks could be installed anywhere no matter the outside climate. This allowed the ice rinks to expand into its prominence today, ranging from recreational activities to professional leagues and international competitions in the Olympics. 

How Does the Ice Freeze?

To ensure that ice rinks can remain stable and frozen throughout their use, an ice rink often has six distinct layers. The skating surface, which is 1/32 of an inch thick, is what most ice rink users feel when skating around. It is created by spraying several thin layers of water on the surface. 

Below the skating surface is a concrete slab, which is embedded with pipes that maintain the ideal temperature of -4℃. The pipes, made of plastic, are filled with an antifreeze called glycol. Glycol, part of the alcohol family, remains in a liquid state despite below-freezing temperatures, unlike water which would freeze and expand. Alternatively, brine, a combination of salts and water, can be used. The two share similar purposes of maintaining the refrigeration system of the ice rink, but a selection of either material can depend on properties such as the preferred viscosity, longevity, and temperature for the antifreeze product. 

The refrigeration cycle involves a chiller, where the heated brine or glycol returns from the surface and is absorbed by a refrigerant, commonly ammonia or carbon dioxide. The refrigerant vaporizes with the absorbed heat, and the brine or glycol can cycle back to the rink. After the refrigerant is cooled back to liquid form, it can now continue back in the cycle to absorb more heat. This allows the pipe to constantly cycle brine or glycol, which is cooler than the surface, to bring heat away from the surface to the refrigerant and maintain the ice rink’s temperature. After this ice mat has been established, the water can be sprayed onto the ice mat to begin creating the ice layers without air bubbles. 

The next layer includes more insulation and a heated concrete layer, which prevents the ground below the ice from freezing and cracking the ice rink itself. This may include styrofoam, which protects the ice from inner heat. On the very bottom, a layer of sand or gravel consists of a groundwater drain. 

Ice Rinks and Sports

To play a game of hockey, lines will be needed to indicate the different sections of play for the game. Two layers of white paint are sprayed in between the first two layers of water, enshrining and freezing these layers of paint. The brightly painted lines, including sponsors and markings, of a hockey rink are typically added on the third water layer. This not only embeds the paint to protect it but also allows the paint to have its glamorous shine once the lights within the complex are turned on. Now, the markings on the ice are illuminated for players and spectators to enjoy their favorite sport. In total, ten thousand gallons of water are used to build the typical National Hockey League (NHL) ice rink, two hundred feet long and eighty-five feet wide, at a rate of five to six hundred gallons an hour to create 12 or more layers.

Depending on the location of the ice rink, such as in an outdoor humid environment, refrigeration systems may need to be adjusted with humidifiers to maintain the frozen nature of the ice in balance with outside temperatures. If the ice rink is located in colder environments such as Canada, the buildings are heated to prevent the ice from being in extremely low temperatures. As water conditions change, ice may need to receive treatments such as chemicals to maintain its firm structure depending on its use. For the NHL, the quality of ice and its conditions can be a subject of concern for players, coaches, and fans; therefore, this only emphasizes the importance of the adaptability of such refrigeration systems to the stadium and local environments to ensure the quality and fair play of the sport. Currently, ammonia is the most common refrigerant for ice rinks due to only requiring small pipe sizes, which is efficient for large-scale refrigeration. Such modifications include a transition to carbon dioxide refrigerant systems as opposed to ammonia, as carbon dioxide is more effective at refrigeration heat circulation at lower temperatures while taking up less space.

Ice skaters prefer what is called “slow ice”, which is softer and has a rougher surface to work with their skates and particular stunts such as jumps and slides. However, hockey players prefer “fast ice”, which is smooth and slippery to help maintain their skates’ grip while skating rapidly across the ice during a game. To maintain the desired level, ice-surfacing machines are used to scrape off a thin layer of ice off the surface, force out dirt and debris, and form a solid bond between new ice (created with a new layer of water) and old ice. At the end, warm water is pumped out and spreads over the ice to fill in deep cuts, quickly freezing with the layers of cold ice below. In fact, the NHL requires that resurfacing is completed before the game, after warm-ups, between periods, and when the game is over to ensure the standard of warm ice for hockey players is met. Your local ice rink, which has hundreds of people skating over the ice every day, requires resurfacing to maintain the cold and standard level of an ice rink with new layers of ice.