T3 Center Arena goes CO2

T3 Center is an ice hockey arena complex, hosting the Swedish 2nd league team Björklöven, with a 5400-spectators-arena and a training rink. In 2016 Umeå Kommun (Umeå municipality) decided to replace the existing refrigeration system in T3 Center.



EKA supported the design and planning of a new 650 kW CO2 refrigeration system using ammonia-water as secondary refrigerant. Further, the new “energy hub” comprises a two stage heat recovery system providing a continuous water temperature of minimum 70°C. The high temperature stage will heat tap water and provide the hybrid dehumidifier with heat for reactivation. A low temperature stage will provide space heating in the arena complex as well as preheating of tap water, subsoil heating and melting pit.


The CO2 refrigeration system including its heat recovery function is designed to utilize the heat recovery properties of CO2. This EKA-developed concept is referred to as the “waterfall principle” which comprises a method of achieving the best possible temperature match between the heating systems and the CO2 refrigerant.