The building uses heat from the human body as energy

More than 250,000 passengers pass through Stockholm Central Station every day, unaware that their body heat is being exploited for energy.

Commuters at Stockholm Central Station move around freely, and the more they move, the more energy they produce, according to Amusing Planet . In 2017, engineers at real estate company Jernhusen in Sweden found a way to take advantage of this excess energy and transfer it to another building in the same area.

Stockholm Central Station welcomes more than 250,000 passengers/day. (Photo: Amusing Planet).

Using body heat to heat a building is not a new idea. Nearly every crowded building like a shopping mall or movie theater does this in the winter to reduce heating costs because the heat from many people increases the natural temperature of the place. For Stockholm Central Station, the difference lies in how engineers collect excess heat and transfer the energy between two different buildings , according to Klas Johnasson, one of the system's creators and head of the environmental department. Jernhusen's school.

The system at Stockholm Central Station works as follows. Heat exchangers installed in the gas ventilation system absorb excess body heat and use it to warm water in underground tanks. The water is then pumped through pipes to the 13-story Kungbrohuset office building more than 30 meters away and integrated into the main heating system. This system is not only environmentally friendly but also reduces the office building's electricity costs by 25%.

The technology is effective in countries like Sweden, where electricity prices are expensive and winter temperatures are very low. Other countries like the US may not see the same financial benefits after investing in insulation, pipes and pumps. In addition, there are some other limitations such as buildings must be located close together, otherwise heat will be lost if it needs to be pumped over long distances. High electricity prices forced Swedish engineers to come up with creative solutions to heat homes.

The heating project at Stockholm Central Station is not the only example of this type of body heat harvesting system. At the Rambuteau metro station in Paris, a similar system has been in operation for nearly 10 years. The heat generated from passengers' bodies as well as the subway train is used to heat apartments located directly above the train station. In Oslo, wasted heat from raw wastewater is used to heat homes. Other projects are also implemented in Finland and Austria. Mall of America shopping center in Minnesota, USA, also uses shoppers' body heat to support the heating system in winter.