While people across the world can take advantage of cold weather by enjoying various sports and activities on frozen rivers, ponds, and lakes, etc., they can also play year-round on man-made ice surfaces. These surfaces can be made specifically for one sport, but often it is a hockey rink so it can be used in various ways. So, how do ice hockey rinks stay frozen?
Indoor hockey rinks use pads of ice which are simply made and kept frozen all year long via a large-scale refrigeration and piping system. This system utilizes a groundwater drain, a base made of sand and gravel which is then covered with heated concrete, insulation, a cold slab of concrete, and water to make the ice surface.
How Does the Refrigeration System Work?
The insulation and heated concrete make sure the ground beneath the ice doesn’t freeze as it may expand and crack the structure of the rink. This system uses a liquid refrigerant, which us usually ammonia and this absorbs the heat from another liquid, which is usually brine, and has absorbed heat from the source. This means it’s an indirect system since the refrigerant doesn’t come in direct contact with the source of the heat transfer.
Brine often used as it’s an anti-freezing calcium-chloride agent. Since it freezes at a lower temperature than the surface water it can flow as a liquid through the pipes. However, it’s still cold enough to freeze the surface water. This refrigeration system also consists of a chiller, compressor and condenser. The brine returns with heat from the surface of the rink at the chiller and is absorbed by colder ammonia. The ammonia boils and vaporizes when it absorbs the heat of the brine. The brine, which is now cooled down, returns to the rink’s surface.
The compressor is used to pull the vaporized ammonia from the chiller which results in lowering the chiller’s pressure. The compressor is designed to pressurize the ammonia gas which raises its temperature from approximately -12 degrees Celsius to over 100 degrees Celsius. When the ammonia gets to the condenser it’s condensed and cooled and returns to liquid form. It’s then circulated back to the chiller where it absorbs the heat from the returning brine, which completes the cycle of refrigeration.
During this continuous refrigeration cycle, the chilled brine is pumped from the chiller to the pipes in the arena floor. This draws heat from the ice surface and keeps the surface temperature constantly cool.
How Cold Do They Keep An Ice Rink?
This system is designed to keep the ice at approximately -4 degrees Celsius for hockey. The temperature inside the rink can be affected by the weather and humidity outdoors which means the system often has to work harder in warmer temperatures.
How Thick Is Ice on a Hockey Rink?
Hockey rinks are created in layers as water is evenly sprayed on the concrete slab at approximately 1/32 of an inch thick. The water quickly freezes on the concrete and forms the base of the rink’s ice surface. More water is applied to the surface in layers until it’s between approximately 3/4 of an inch to one inch thick.
If the rink’s ice is too thick it takes more energy and time to freeze and the top of the surface may not be hard enough, making it slow and soft. On the other hand, if the ice is too thin, skate blades could possibly cut through it and expose the concrete.
How Do they put Logos on Hockey Ice?
After the first few layers of water are applied to the concrete slab and freeze, the ice surface is typically painted white and the blue lines, goal lines, logos, and faceoff dots and circles, etc are also painted on.
How is the Ice Surface Maintained?
Since the ice surface deteriorates during a hockey game due to skate blades digging into it, it’s maintained on a regular basis with a surfacing tractor, typically known as a Zamboni. This machine is driven on the ice surface and is designed to gently scrape and shave the ice while it collects loose shavings and snow.
When the ice has been scraped the Zamboni leaves a thin layer of warm water on the ice which freezes and creates a fresh smooth surface. If a rink doesn’t have a Zamboni, the surface can be maintained by shoveling off the loose ice and snow and then sprayed evenly with a thin coat of water which will eventually freeze.
How Many Gallons of Water does a Zamboni use?
The standard ice surface of an NHL rink is 200 by 85 feet and it generally takes between 12,000 and 15,000 gallons of water to create it. It’s estimated that a Zamboni uses between 200 and 275 gallons of water each time it’s resurfaced. Since an Olympic-sized rink is 200 by 100 feet, it will take more water to resurface the ice.
Ian is an experienced ice hockey writer with a passion for the game. He has been covering hockey for over 25 years and has contributed to various publications. He covers all aspects of the sport, from NHL rules to in-depth analysis of the game as well as previews. Ian is also an avid fan who attends numerous games and has played hockey regularly since moving to Canada at the age of 10.
