Evolution of CO2 as refrigerant in ice rink applications.

The first ice rink system using carbon dioxide, CO2, as secondary refrigerant was built in Austria 1999. It would take until 2010 in Canada until the next generation, using a trans-critical CO2 solution, was realized for the first time. That eventually the ice rink business moved to trans-critical CO2 systems was a very natural step considering the 1st generation systems using CO2 as secondary refrigerant, and the parallel development of trans-critical CO2 systems in supermarkets. Ice rinks and supermarkets are rather similar when it comes to cooling capacity and heat recovery requirements which implies that the system design and associated control could easily be carried over to the ice rink applications. CO2 as refrigerant in both direct and indirect ice rinks systems where proposed several times before it eventually happened in 2010. The reason why it took so long before the ice rink industry accepted these systems is probably because there were no customers ready to take the risk and the somewhat higher cost for installing them. The most recent CO2 ice rink systems have demonstrated that essentially any ice rink can be self-sufficient with heat and that the overall energy efficiency is taken to a new level due to the unique properties of CO2. Today we see a rapid growth in the number of CO2 ice rink systems in Canada, the U.S. and Sweden, which is most likely just the beginning.