Bahcohallen used to be a typical ice rink with a heated arena room (about 8°C). An ammonia refrigeration unit was connected to a calcium chloride circuit in the
ice rink. The system's heat recovery function delivered up to 28°C for preheating the facility's air handling unit.
In 2016, this was replaced with a new CO2 refrigeration system based on direct expansion, where CO2 also circulates in the ice rink's new copper pipes laid in a concrete layer above the existing ice rink floor. In addition, the facility was supplemented during the 2017/2018 season with a second ice rink in a heated arena room (about 10°C) in a brand-new building next to the existing ice rink. An optimized heat recovery system connected to the CO2 system is designed to cover a large portion of the heating demand in both ice rinks.
In fact, the two ice rinks use only 10% more energy than the old facility. This means that the owner now operates two ice rinks for almost the cost of one!
The new refrigeration unit and its heat recovery function led to a 15% reduction in energy consumption - from 4.72 to 4.00 MWh/activity day - when the facility still consisted of only one ice rink. However, at this stage, the heat recovery function was not yet used to its full capacity, and the size of the energy savings for the new system solution became clearer only when the new ice rink was also connected to the system during the 2017-2018 season.
Today, the single-stage heat recovery system covers 97% of the ice rinks' heating demand - including dehumidification. In fact, the two ice rinks use only 10% more energy than the old facility. This means that the owner now operates two ice rinks for almost the cost of one!
When EKA designed the heat recovery function in 2015, it was assumed that a new swimming pool would be built next to the ice rinks, so a heat export function was integrated into the system solution. Today, the swimming pool is also completed, and the ice rinks have an estimated annual surplus heat of 700 MWh, which will now be available for its heating demand. To fully utilize the heat export potential, the owner, Enköping municipality, will in the future operate at least one of the ice rinks year-round. This is good energy management!