The recently remodeled Dollard-des-Ormeaux Civic Centre in Quebec, Canada uses a carbon dioxide refrigeration system to freeze the floor of the ice rinks as well as provide building heating. The details of this project were published in a paper titled “CO2 Showcase for Ice Rinks, Pools” by Kateri Heon and Pietro Guerra from exp. Inc. in the August, 2015 ASHRAE Journal.
According to the authors, what immediately emerged from the study was that:
- CO2 offered significant advantages for the project, compared to ammonia. This is despite ammonia compressors having an average coefficient of performance (COP) value of 3.45, which is considered excellent for the temperature requirements associated with an ice rink. Ice rink refrigeration systems typically release heat through a glycol loop that cools the compressors and can reject heat in several heating coils or through heat pumps in the building. Because CO2 refrigeration systems operate at very high pressure and, therefore, at high temperature, it is possible to reject the heat from the refrigeration system into a high-temperature water loop (160°F to 180°F [71°C to 82°C]).
- At the Dollard-des-Ormeaux Civic Centre, the high-temperature loop heated by energy recovered from the CO2-based refrigeration system contributes to heating pool water, domestic hot water and two small glycol loops that provide heating for the players’ locker rooms, and the main pool area and changing rooms.
- CO2 can be circulated in the building, as opposed to ammonia, which is too toxic. CO2 is not a highly viscous fluid, and the high operating pressure of the system means it can easily be moved. Given these advantages, CO2 was used to heat the stands of the Centre’s three ice rinks, with CO2 coils installed directly in the system’s air ducts. This method avoided having to provide the pumping power required for a glycol loop and optimized the efficiency of the exchange.
- And, like ammonia, CO2 has little impact on the environment.
Over the past decade, CO2 refrigerant systems have gained growing acceptance as an alternative to traditional HCFC (hydro-chlorofluorocarbon) type R22 refrigerant or ammonia-based systems in the food and food transportation industries. However, it was not until 2010 that the world’s first 100% CO2 sub-based refrigeration system used in an ice rink was completed in Marcel Dutil Arena in Quebec.
In 2012, a Comparative Study of refrigeration systems for ice rinks in Quebec was undertaken by Natural Resources Canada’s CanmetENERGY Research Centre. They compared 12 typical refrigeration systems currently offered for ice arenas in the market, and found that a CO2/R744 system as being the most energy efficient, while a CO2 plus brine system as the least expensive.