Project Details

Hot Heart is a winner of the Helsinki Energy Challenge. The challenge sought designs to decarbonise the heating of the Finnish capital by 2030. We worked alongside CRA to create a vision film that explains the design’s concept and benefits to the city. Our jargon-free approach helped engage an international jury with the opportunity, placing our team as one of four winners.


CRA-Carlo Ratti Associati


Helsinki, Finland


Green Technology


CRA-Carlo Ratti Associati, Ramboll, Transsolar, Danfoss Leanheat®, Schneider Electric, OP Financial Group, schlaich bergermann partner

The Brief

‘Create a vision film for the Hot Heart that helps to communicate the concept and its wider benefits to an international audience.’

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Our Response

The film narrative has simplicity at the core. It acts as an instruction manual for the audience, explaining the Hot Heart concept. We chose to help the audience imagine a future where the Hot Heart is already benefiting the city – both by offering decarbonised and lower cost heating and by providing a unique recreational venue.

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The instruction manual approach also acts as a metaphor for how this concept can be taken and applied to other cities around the world. Our film demonstrates the dual nature of the design and the solutions Hot Heart can offer similar cities.

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Hot Heart will be the largest infrastructural facility of its kind. The system functions like a giant thermal battery: low- or negative-cost renewable energy is converted into heat, stored in the tanks and withdrawn into the city’s heat distribution channels during the winter. The design also doubles as a unique recreational venue, with four of the 10 hot water reservoirs containing ‘Floating Forests’ and pools. These create a unique public space for residents and provide an attraction for international travellers.

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