In total, the energy use of the ice rink went down by 18%
"Hällevi ishall" is an indoor single sheet ice rink with a tempered arena room (7-8°C) and an 8 months season in the south western part of Sweden. The new indirect refrigeration system based on CO2 with its heat recovery function has today been in operation for one whole ice season, with very promising results. The district heating bill is down by close to 100% compared to the old ammonia refrigeration and heat recovery system. Even though the heat recovery function of the CO2-system has been fully activated the electricity bill has remained the same or even somewhat lower. In total, the energy use of the ice rink went down by 18% or 96 MWh compared to the old system solution.
This indicates that the heating demand of Hällevi ice rink with a capacity of 1000 spectators can be fully covered by the reclaimed heat from its new refrigeration system, while district heating is only kept as a backup solution. Furthermore, there is plenty of released heat that still could be used for other heating purposes and the municipality has plans to potentially build a swimming hall next to the ice rink which enables the possibility for heat export.
In 2016 EKA designed the new CO2 refrigeration system comprising a two-stage heat recovery solution. High grade heat is used for traditional heating purposes as well as reactivating the new dehumidifier. The new refrigeration system was connected to the existing rink floor distribution system designed by EKA in 2014, where ammonium hydroxide (aqua ammonia) replaced calcium chloride as the secondary refrigerant which significantly reduces the pumping power.