Mäntsälä combined data and heat

Waste heat from a data centre is transformed by heat pumps to supply heat in the local district heating network

The city of Mäntsälä is located in the south of Finland and has a population of over 20,000 inhabitants. It represents a good practice example, where the municipality buys waste heat from a local data centre to supply heat in the city. No less than 1,500 houses in the city are currently supplied using district heating, but in the future, approximately 4000 houses will be connected to the network. In the first phase, the heat in the data centre is collected using heat exchangers, transforming the warm air into liquid. Then, in the second phase, the 4 MW heat pumps in the district heating plant rise the temperature of the water from 40 to 85°C. The heat pumps are optimised to achieve high temperature and high COP, over 4. It is estimated that the heat provided in the first phase is enough to provide the baseload in the summer, thus approximately 75% of the heat in the city comes from clean energy sources. Therefore, the need for fossil fuels is reduced dramatically, and at the completion of the project, the CO2 emissions are expected to be reduced by 22,000 t/year.

District Heating scheme

Technical details of the application

  • Heating capacity: 3600 kW
  • COP: 3,4
  • Refrigerant: R134a
  • Heating source: Data center exhaust air to water