Body Heat Heating Building in Stockholm

The body heat from Stockholm central station’s 250 000 daily commuters now warms the office block next door, slashing heating costs by 25%.

Living heat sources - The commuters of Stockholm Central Station contribute to the local district heating network. Photo: Michell Zappa, Wikimedia Commons

Saving energy is often just about being creative, and using the resources that are right in front of your nose. Jernhusen, a Swedish real estate firm, has found a way to utilise excess heat from the train station to provide affordable and sustainable space heating to an office block nearby.

“Why shouldn't we use this heat? It's there. If we don't use it then it will just be ventilated away” - Klas Johnasson, Jernhusen

Stockholm’s Central Station is the largest and busiest train station in Sweden. The combined energy from the commuters and shops in the station generate an enormous amount of heat that is usually ventilated away. But thanks to some innovative thinking this problem is now a solution.The station has teamed up with an office building across the street, to transfer the energy through heat exchangers and into the building’s waterborne central heating system. This cheap, renewable energy source is estimated to reduce the heating costs of the building by up to 25% compared to using natural gas.

Although heat exchangers are not a new technology, the challenge is to transfer the heat from one building to another. This requires a long-term collaboration between owners of the two buildings.

With their freezing winters and high energy prices, Swedes are used to looking for alternative sources of heat. Many Swedish houses and buildings are heated by district heating – hot water pumped through insulated pipes, often from biomass-fired combined heat and power plants.

Globally, human body heat is hardly a scarce resource. Stockholm's Central Station may be an example to others in the search for new heat sources. All it takes is the ability to look for new solutions, and a bit of cooperation.

The Kungsbrohuset office building has 40 000 m2 in floor space and was built by Jernhusen in the district of Västra City in Stockholm. In addition to using excess heat from the central station, it deploys several solutions such as maximising the use of natural daylight, and using water from a lake for cooling.