Hot Heart was developed as part of the Helsinki Energy Challenge organized by the municipality of Helsinki to accelerate the city’s transition towards carbon-neutrality in heating by 2030. The competition was attended by 252 teams from around the world and the 10 best entries were selected for the final. Ramboll delivered the technical ideation and design of the proposed solution as part of the team led by the Italian design and innovation agency Carlo Ratti Associati.
Hot Heart 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. The project is highly adaptable and could be replicated by other cities with similar climatic characteristics pursuing sustainable heating solutions.
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 meters in diameter. They collectively can hold up to 10 million cubic meters 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like a giant thermal battery: low- or negative-cost renewable energy is converted into heat, stored in the tanks, and withdrawn into the city’s heat distribution channels during the winter.
“There are excellent conditions for wind power generation Finland. Wind power generation has evolved in recent years and is, in fact, the cheapest way to generate electricity. Further, electricity generated by wind power using heat pumps is also the cheapest way to produce district heat”, says Jouni Laukkanen, Director at Ramboll Finland and continues:“However, it is not always windy. Thanks to the proposed huge heat storage, the use of electricity in district heating production can be timed to windy times and the annual variation in heat demand can be significantly balanced. A similar solution would be applicable to all district heating networks”.