The Wasahallen in Filipstad was built in 1989 and initially had R22 as refrigerant, which was later converted to R404A. The plant had a certain amount of heat recovery and the electricity consumption was annually 800 MWh on average to keep the 3,570 m2 large plant with heat and hot water. In addition to the arena room's 2,600 m2, there are 970 m2 of heated areas such as changing rooms, cafeteria, workshop
and club room.
EKA carried out an inventory in the autumn of 2017 and proposed an overall upgrade to get rid of the environmentally hazardous refrigerant and to be able to save on operating costs. The plan contained mainly; new CO2 cooling system with heat recovery (HR), connection of the entire building's heating system to HR, replacement of secondary refrigerant, new dehumidification unit, and a completely new control/monitoring system. In addition to this, an old oil boiler was scrapped, an electric boiler was removed and some smaller previously directly heated spaces were provided with hydronic heating system.
Before renovation
In addition to developing the package of measures, EKA also made an energy and profitability calculation that formed the basis for the customer's investment decision. The energy savings were calculated at the range of 35-40 percent, which corresponds to energy use of approximately 480 MWh per season. This can be compared with previously about 800 MWh, which includes "the big five", ie all the essential energy systems (cooling, heating, dehumidification, lighting, and ventilation).
After renovation
The renovation was carried out in 2018 and was completed just in time for the start of the season the same year. Today, the new systems have been in operation for two seasons and are halfway into the third. Now a carbon dioxide cooling system cools and heats the plant with a marginal tip from electricity. The secondary refrigerant has been changed to ammonia water, which halves the electricity use for the brine pump. The dehumidification is done with recycled heat and the air is distributed in new textile ducts. Spaces that previously lacked heat or were heated directly receive heat today from the recovery system. Today, the various parts of the plant can be controlled and monitored remotely, and process and energy data are saved for follow-up. In short, it is a modern facility.
Recently, a summary has been made of the operation of the first two seasons, with the new system, and compared with the time before the rebuild. The reference period is calculated as an average value for the three seasons before the renovation and compared with the average value of the last two seasons, a decrease of 39.2 percent can be seen. In practice, this means that energy consumption has decreased by approximately 340 MWh and is now around 460 MWh on a seasonal basis. Converted to a monthly basis, this means that the total energy consumption is in the range of 50-70 MWh per month depending on the ambient temperature. Finally, it can be stated that the real savings are in good agreement with the calculation made before the project was carried out. The fact that it then also became a lower investment cost than expected does not make matters worse!
“Naturally energy efficient by EKA!”