Recycling Urban Heat

In urban areas, buildings and concrete surfaces create a heat effect that can make temperatures in the city substantially higher than in nearby rural areas. That heat isn’t just above ground, either. It seeps into the subsurface, measurably increasing groundwater temperatures. In a recent study, authors suggest this excess subsurface heat could be reclaimed and recycled (via heat pumps and other heat exchangers) in urban areas to offset peoples’ needs and to help groundwater return to its normal temperature. They found that even focusing on heat stored in the top meter of the subsurface could provide green heating for much of the world’s urban populations. (Image credit: J. Dylag; research credit: S. Benz et al.)