Human heat is a pretty powerful thing. Aside from curing hypothermia and keeping energy bills low in households that cuddle for warmth, it can be used to heat buildings.
In Stockholm Central Station, over 250,000 commuters pass through the station each day, making it the busiest train station in northern Europe. And 250,000 bodies can generate a lot of heat.
The way is works is excess heat in the station can be extracted through heat exchangers in a ventilation system. This ventilation system can also provide air conditioning. The excess heat in the ventilators gets converted into hot water.
Then, if that already wasn’t enough, the water gets pumped to the building close to the train station to serve as a part of its heat supply. The office blocks save up to 25 percent on energy bills from the human heat provided by the commuters. Cool, eh?
(Spotted on BBC)