#TIL: Mobile human heaters of Stockholm

By Chhavi Banswal

Waiting area at Stockholm Central Station. Photo credit: Johan Berhin, 2013.

As the world scrambles towards renewable sources like wind and the sun to meet its energy needs, Stockholm has decided to turn to its population instead — using humans as a source of heat. Jerhusen, a Swedish real estate company, uses technology to harvest surplus body heat from commuters at Stockholm Central Station, to channel it to another building.

According to scientists, a resting human gives off approximately 100–120 Watts of energy. The Station sees an average footfall of 2,50,000 commuters a day, not just passing through but also browsing across shops and spending time at eateries. All these activities generate body heat, which is absorbed by the heat exchangers installed in the Station’s ventilation system. The heat is then transferred to warm water in underground tanks, which is supplied to the main heating system of a building across the street.

Rabuteau Métro station in Paris has been operating on similar lines for more than a decade. The apartment complex built on top of the underground train station is heated through the transfer of heat from the commuters. Such a technology could work wonders in cities like Delhi, where the average daily footfall at two of its busiest metro stations — Kashmere Gate and Rajiv Chowk — was 2,44,433 and 2,25,438, respectively, in 2019.

Harnessing body heat is not just environment friendly, but can also reduce the energy cost of the building using it by 25%. The technology, at the moment, could be exorbitant for a country like India, as it requires additional installation expenses like insulation, pipes and pumps. However, it has the potential to utilise urban heat distribution networks in the long run, which are abundant in developing countries with high population density.

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