An ambitious new project led by Carlo Ratti Associati (CRA) could provide Helsinki with a sustainable source of heat and double as an attractive location for Fins to escape the long harsh Nordic winter. Named Hot Heart, plans call for a series of manmade islands that will store thermal energy and use some of that heat to create a tropical paradise.
Assuming it actually goes ahead, Hot Heart will be situated off the coast of Helsinki and consist of an archipelago of 10 manmade islands that can be thought of as huge water basins. Each will measure 225 m (738 ft) in diameter and hold up to 10 million cubic meters (roughly 35 million cubic ft) of water.
According to CRA, the system will act like a big thermal battery. So, using heat pumps, energy drawn from wind, solar, and other renewable sources will be converted into heat, stored as hot water in the tanks, then withdrawn and pumped into the city's heat distribution network as required. CRA told us that the system would work with existing renewable energy sources and adapt as the numbers of solar panels and wind turbines in the country continue to grow. More impressive still, it could eventually provide all of Helsinki's heating needs.
Additionally, thanks to all the heat being produced, four of the islands will be able to serve as recreational destinations, with pools and tropical forests and plants installed. The idea is that they will be encased with a transparent dome and LED lighting, allowing locals an escape from the winter chill (presumably they'd need to be reached by boat but such practicalities aren't addressed at this early stage).
"Production of renewable energy is getting cheaper, but storage is still extremely expensive," says CRA. "Our idea is to use the giant 'thermal batteries' to store energy when prices are at low or even negative levels, and extract it when required by the district heating system when demand is high. This model would also be applicable to many coastal cities with similar climates.
"CRA worked with an international group of consulting and manufacturing firms and energy optimization experts to develop the project's central concept: using seawater heat pumps to convert wind, solar and other forms of power into heat, which is stored in Hot Heart's reservoirs. The system, operated by artificial intelligence, synchronizes the production and consumption of thermal energy, which helps stabilize the national energy grid in relation to fluctuating supply. The whole system is expected to cover the entire heating needs of Helsinki, estimated at 6,000 GWh, by the end of the decade, all without any carbon emissions and at an estimated cost 10 percent lower than today"
Clearly it's an ambitious project with lots of potential issues and it's only early days yet, but Hot Heart recently won the Helsinki Energy Challenge competition and CRA hopes that it will be realized by 2028. The project was developed in collaboration with Ramboll, Transsolar, Danfoss Leanheat, Schneider Electric, OP Financial Group, Schlaich Bergermann Partner, and Squint/Opera.
The idea is not without precedent as over in Denmark there's a plan to build a series of islands that provide recreational space and energy production, while BIG's Copenhill is another example of combining sustainable energy production with recreation.
Source: Carlo Ratti Associati
