Waste Heat Potential Study of Cooling Water Towers in Koskenkorva (Ilmajoki)

Use of the full waste heat potential of the plant and reduction of emissions through energy improvement.

Implementing Partner: District Heating Kurrika, Thermopolis Ltd.


Contact person: Sauli Jäntti, sauli.jantti@thermopolis.fi, Petri Viinikainen, petri.viinikainen@kurikankaukolampo.fi


Implementation phase: October 2018 to March 2020


Financed by LowTEMP project: 19.190 EUR (planning)

Financed by partner: 8.230.000 (design, coordination and construction, total calculated investment cost)


District Heating Kurikka, Ilmajoki municipality, house owners, production company Altia Oy

Overall aims

  • Ability to use the full waste heat potential of the plant of Koskenkorva: A considerable amount of thermal power is released from the site, but when the waste heat temperatures are relatively low and due to the lack of a sufficient district heating network, the thermal power has not been utilized in the heat use of other sites so far.

Environmental effects:

  • Reduction of emissions through energy efficiency improvement

Innovative approach and benefits

The outcome of the study confirmed the potential of the waste heat utilisation (about 30,000 MWh of DH could be produced by waste heat, with a maximum power of about 4,5 MW). In addition, this would allow for a shift away from or a reduction in some fuels, such as peat and oil.

The factory process releases heat via cooling towers when it could be available for heating use. If waste heat can be utilized in the future, this will enable the development of low-heat networks (separate networks) in the area.

The waste heat of the Altia Oy, Plant of Koskenkorva cannot utilize its full waste heat potential in district heating use, as the district heating network’s power curve varies with the seasons. Only the power supplied to the district heating network is considered in the calculation. The heat is raised by a heat pump with the Coefficient Of Performance (COP) of 3. The maximum temperature of the water leaving the heat pump is 85 ° C (the selected technology limits the maximum temperature). In addition, prime power is needed to raise the temperature to the required temperature levels in winter.

A direct investment in a low-heat network would be very significant for the company, and if this includes the replacement of the building stock (including heat exchangers), etc. and possibly the renovation of properties, it would be too large to do at once.

The waste heat recovery solution will be considered in the context of the company’s future investment needs. For example, waste heat utilisation should be considered (beside other alternatives, such as new solid fuel boilers or other) as an alternative to replace old solid fuel boilers.