Hot Heart Helsinki

CRA-Carlo Ratti Associati have been using SpaceForm throughout the initial design phases for their winning solution to help decarbonise Helsinki's heating network

In 2021, CRA-Carlo Ratti Associati’s Hot Heart project was one of four winners of the global Helsinki Energy Challenge, with a proposal to create island-like, floating sea water reservoirs to heat the city in a green way. The competition was launched to find sustainable alternatives for urban heating networks, using Helsinki as a testbed. 

CRA have been using SpaceForm throughout the initial design phases for their winning solution to help decarbonise the city's heating network.

The Italian architecture studio’s project is based on an archipelago of heat-storing basins with the dual function of storing thermal energy and serving as a hub for recreational activities. The “islands” will also be home to tropical forests and ecosystems from around the world, giving the Finnish capital additional public space and a new educational attraction. They are using Twinmotion, Epic Games’ real-time visualisation platform for the architecture industry, to design the project. 

CRA have been working in collaboration with SpaceForm’s revolutionary, data-driven virtual design platform, to virtually communicate their competition-winning designs. Hosted in the cloud, SpaceForm is a more sustainable way to meet, collaborate and design remotely.

Located off the coast of Helsinki, Hot Heart will be the largest infrastructural facility of its kind. The project consists of a set of 10 cylindrical basins, each measuring 225 metres in diameter. They collectively can hold up to 10 million cubic metres of water. 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like a giant thermal battery: low- or negative-cost renewable energy is converted into heat, stored in the tanks, and withdrawn into the city’s heat distribution channels during the winter.

CRA are currently exploring ways to develop the first prototype, a single basin in slightly smaller dimensions – a fully functional hot water reservoir with public amenities on top, to test public reaction.
Hot Heart is projected to be fully implemented in 2028.

Find out more here.


Hot Heart is an international collaboration for the Helsinki Energy Challenge developed by the teams below:

CRA-Carlo Ratti Associati (Design)

Ramboll (General Engineering) – Mika Kovanen, Kreetta Manninen

Transsolar (Climate Engineering) – Monika Schulz, Thomas Auer

Danfoss Leanheat® (Demand Management Engineering) – Oddgeir Gudmundsson, Jukka Aho, Juho Nermes, Lauri Leppä, Nico Klecka

Schneider Electric (Technology Partner for Sustainability and Energy Efficiency) – Jani Vahvanen

OP Financial Group (Financial Analysis)

schlaich bergermann partner (Lightweight Structural Engineering) – Mike Schlaich, Boris Reyher

Squint/Opera (Communications Partner)

CRA team: Carlo Ratti, James Schrader (Project Manager), Alberto Benetti, Federica Busani, Rui Guan, Stephanie Lee, Juan Carlos Romero and Chenyu Xu

Renderings by CRA graphic team: Gary di Silvio, Pasquale Milieri, Gianluca Zimbardi

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