Underground car parks act like heaters for the ground and according to a new research from Germany and Switzerland, the energy this generates could be used to heat buildings. Researchers from involving Germany's University of Halle and the Karlsruhe Institute of Technology, as well as Switzerland's Basel University analysed the temperatures in 31 underground car parks in various cities in Germany, Austria and Switzerland. In six of them, they were also able to measure the temperature of the grou