Geothermal using body heat

The Power of a Hot Body – catchy title, and a good idea.  Why waste the heat generated by hundreds of people waiting in a subway station and the friction of trains on tracks?  This NYTimes opinion piece cites examples from Paris, Minnesota, and Sweden.

Idly mingling, a human body radiates about 100 watts of excess heat, which can add up fast in confined spaces. …

Savvy architects from Paris Habitat decided to borrow the surplus energy from so many human bodies and use it to supply radiant under-floor heating for 17 apartments in a nearby public housing project, which happens to share an unused stairwell with the metro station. …

… the four-million-square-foot Mall of America, where even on subzero winter days the indoor temperature skirts 70 from combined body heat, light fixtures and sunlight cascading through ceiling windows.

Or consider Stockholm’s busy hub, Central Station, where engineers harness the body heat issuing from 250,000 railway travelers to warm the 13-story Kungsbrohuset office building about 100 yards away. …

Widening their vision to embrace neighborhoods, engineers from Jernhusen, the state-owned railroad station developer, are hoping to find a way to capture excess body heat on a scale large enough to warm homes and office buildings in a perpetual cycle of mutual generosity. Heat generated by people at home at night would be piped to office buildings first thing in the morning, and then heat shed in the offices during the day would flow to the residences in the late afternoon.

More on these projects that capture body heat for reuse:  Ideas for Cities: Geothermal Stations Which Harness Heat from Crowds and Innovation, commuters and spies: the extraordinary tale of Stockholm’s greenest building.  The International Geothermal Association doesn’t have much on this concept, but it does have a great list of links to  geothermal organizations around the world.

Many thanks to Jim Richert for forwarding the initial opinion piece.  Image is of Kungsbrohuset (source).