Turning Subway Tunnels into Geothermal Heat-Recovery systems - Goodnet
Go into almost any subway station, and it's probably going to be almost unbearably hot at this time of year. You would think that going underground would chill things down, but tunnels don't work that way. The heat from trains, crowds of people, electronics like lights, and signals all add up to make them really warm. Now, researchers have found a way to use all that hot air.
Researchers at the Swiss Federal Institute of Technology in Lausanne, EPFL, have looked at the heat transfer numbers in the heated air in train tunnels and designed a geothermal heat recovery system that could be used to provide heat and cooling to thousands of nearby houses.
Scientists have been aware of the potential energy in subway tunnels, but they weren't able to calculate it accurately. But now, the researchers from EPFL have solved the puzzle, according to an article in New Atlas. The team found a way to develop a model that allows them to very precisely calculate the convection heat transfer coefficient of individual tunnels.