According to the International Ice Hockey Federation (IIHF)’s new Guide to Sustainable Ice Arenas, improving the energy efficiency of an ice arena is one of the most important ways to make the facility more sustainable.
The guide, which was authored by Swedish refrigeration consultancy Energi & Kyanalys (EKA), highlights optimizing heat recovery from an ice rink’s refrigeration system as a top energy priority.
“An ice rink with a tempered arena room [5–10°C/41–50°F] uses about the same amount of heat as cooling,” explained the guide. “The largest energy savings potential can often be found in optimizing the heat recovery from the refrigeration system, and therefore minimizing the demand for a supplemental heat source. In most cases this also implies that the ice rink owner benefits from an increased economic performance of the facility.”
Made publicly available last month, the guide offers a general technical overview of ice arenas with a focus on their energy systems. It aims to provide ideas on how to make ice rinks more sustainable, largely through reduced energy consumption, and looks at both passive and active solutions.
“Sustainable ice rink technologies consist of long-term solutions that lead to optimum function in a way that manages resources efficiently,” said the guide.
69% of energy use
Ice arenas have five basic energy systems – refrigeration, heating, dehumidification, ventilation and lighting – which combined, account for 90% of the facility’s energy use.
In most conventional ice rinks, refrigeration accounts for 43% of energy use while heating uses around 26%. As significant consumers of energy, a facility’s refrigeration and heating systems often present largest savings potential.
While there are a number of “quick fixes” that can offer some efficiency improvements and minor cost savings, substantial benefits can be realized with longer-term solutions, which have been proven to cut energy costs by more than 50%.
For example, at an ice rink in Pirkkala, Finland, a new CO2 (R744) refrigeration system helped the facility reduce its electricity consumption by 34% compared to its previous R404-based system. Operating on less than 1.4MWh of electricity per day, it is now one of the most efficient ice rinks in the world, according to EKA.
The average ice arena uses more than 3MWh of energy per day during the ice season, which runs between August and March.
NatRefs are ‘optimum’ choice
In addition to improving the energy efficiency of a refrigeration system, the environmental impact of its refrigerant is also becoming an increasingly important decision, according to the guide.
While there are a number of options available to ice rink owners, CO2 and ammonia (R717) are the “optimum” choice for primary refrigerants, it adds.
Synthetic options like ozone-depleting HCFCs and high-GWP HFCs are being phased out or down in most parts of the world under the Montreal Protocol and its Kigali Amendment.
HFOs are another synthetic option and while they are not an ODS and often have lower GWP than HFCs, “several studies have reported about other environmental and health concerns that HFOs introduce,” the guide explained.
For natural refrigerants, propane (R290) has become more popular in recent years, but concerns around flammability limit its adoption.
Ammonia is highly efficient and is widely used in indirect refrigeration systems where low-charge ammonia is used as the primary refrigerant to limit the risk of toxicity in the event of a leak.
According to the guide, CO2 is generally less efficient than ammonia, particularly in warmer climates, but due to its non-flammable and non-toxic properties, it is growing in popularly as synthetic alternatives are phased out. CO2 also offers greater heat recovery potential, which means that for facilities that require both cooling and heating, R744 can often be the most energy- and cost-efficient solution.
According to another study by EKA, CO2 refrigeration systems can also help control humidity levels in ice rinks.
CO2 for heat recovery
While CO2 wasn’t used as the primary refrigerant in an ice rink until 2010, there are now a growing number of ice arenas across Europe and North American that use R744-basedrefrigeration.
A large driver in the adoption of this technology has been its heat recovery potential.
According to the guide, an optimized heat recovery system can often cover the facility’s entire heating demand even during the colder months, completely eliminating the need for an external heating source. In some cases, systems have proven to be so efficient that they can also export heat to neighboring facilities like swimming pools.
In addition to being implemented in new ice rinks, heat recovery systems can be added to existing facilities.
In Gimo, Sweden, a facility that used to rely on district and electric heating for its heating needs is now self-sufficient thanks to the heat recovered from its CO2 refrigeration system, which was installed before the 2014 season. The ice rink had previously used an ammonia-based system.
In Testebovallen, Sweden, an indirect CO2 system with aqua-ammonia secondary replaced the existing HFC system at an ice rink. The upgrade significantly reduced electricity and district heating demand.
At an ice arena in Bahcohallen, Sweden, a new CO2 system is able to run two ice sheets with an energy consumption that is only 10% higher than what the previous ammonia system needed when running one ice sheet. The upgrade has also minimized the use of district heating.
In 2019, an ice rink in Eksjö, Sweden, replaced its existing ammonia system with an indirect CO2 system. The next year, the old ice sheet was also upgraded. The two updates a have significantly reduced the facility’s electricity and district heating requirements.
Other examples of using natural refrigerants in ice rink refrigeration systems can be found in the North American Guide to Natural Refrigerants in Ice Arenas, which was produced by ATMOsphere, publisher of R744.com.