Paris is a tourist destination of choice for many reasons. Thankfully, a convenient and extensive rail system allows one to navigate around the city to see and experience all those reasons—and it is especially useful if you happen to transit through Charles de Gaulle airport and have a long layover. The Paris Metro also gives rest to weary feet after walking around the Latin Quarter, the Marais, or wandering lost around La Défense for a business appointment.
Of course, like many public transport systems, summer, and even other times of the year, can generate some body heat—almost as much as the eponymous 1981 movie. And when a system like that of Paris Metro hauls 4.5 million people a day, those heat calories have got to go somewhere. Now a public housing project in the city’s center will benefit from all those commuters darting across Paris.
Located on rue Beaubourg, close to the Rambuteau station, the building will draw heat from all those passengers, who on average generate about 100 watts of energy per ride. Based on the principles of geothermal technology, heat will push from the station to heat exchangers, which will then flow through heating pipes. A request for proposal will be issued by the city government before the end of this year, and work will begin in 2011. Should the project progress as planned, 17 flats will receive heat from this method. The new system will also reduce carbon emissions by one-third through the replacement of a boiler currently used in the building.
It all sounds great, but do not expect all those commuters to get rebates for their subway passes. The project is feasible because a passage connecting the building to the subway station already exists. For now the technology is too expensive to implement all over Paris. So think of this project as a laboratory for similar initiatives around the world; for example, Stockholm is tinkering with a similar plan that transfers heat from its central rail station to an office building. Cities with a high population density like Seoul or Tokyo could be a natural for such a passive heating system. Of course, if fossil fuel prices spike again in the near future, it could push ideas like this from the occasional one-off renovation to a mainstream approach. If you see engineers tapping the walls of your subway exit while you march to the office . . . you will know why.