By using a 158 kW steam-temperature heat pump supplied by Ochsner, the capacity and the efficiency of the district heating system in Mänttä-Vilppula is increased, without enlarging the capacity of the power plant, respectively of the boiler. Therefore, in this application, the return line of the district heating system, with a temperature level of 45°C to 55°C is used as heat source for the heat pump. The heating capacity of the heat pump is used as a supply line for a local district heating system.
Depending on the outside temperature the heat pump delivers hot water with a temperature between 70°C and 120°C, but the same device could also supply flow temperatures of up to 130°C. The heat pump was commissioned in 2017, achieves an annual COP of over 2,0 at highest flow temperature and uses the non-flammable and non-poisonous refrigerant ÖKO 1.