Hybrid system taps into natural sources

• Finnish manufacturer combines waste heat and geothermal in its hybrid heating and cooling system
• The clever system cut annual energy costs by € 100 000 and carbon emissions dropped by 310 000 kg

Kiilto is a Finnish manufacturer of chemical industry products. At their Lempäälä factory, chemicals for construction and industry are produced. In glue production, polymerisation is an important production stage which releases a lot of thermal energy. The reactor also requires cooling during this process.

In 2018, Kiilto started utilising the waste heat from the glue manufacturing process to replace a natural gas-based heating and cooling system, provided by Calefa Oy.

The unique hybrid system connects thermal pumps for the waste heat to a geothermal heating and cooling system. Excess waste heat is stored in bedrock for later use. The geothermal system gives thermal energy for heating the premises during the night, and the geothermal wells are cooled down. This geothermal cooling is used to cool down the production process, which then results in the geothermal wells heating up again, and the heat exchange can be repeated.

Optimal utilisation of the waste heat is ensured through remote monitoring and optimisation by Calefa Oy. The system uses waste heat from temperatures as low as 15 to 20 degrees.

The system has even helped to increase polymerisation production capacity, which no longer needs to plan the production according to the fluctuations in cooling water capacity. The temperature remains stable during the entire process, which allows for more homogeneous production.

Key benefits

• The hybrid system boosted the company’s energy savings: in a year, energy costs were decreased by € 100 000 and carbon emissions dropped by 310 000 kg per year
• The need to burn natural gas for heating decreased by 1 800 MWh
• Improved cooling also increased production capacity and reliability of delivery