The heat given off by car engines warms up underground car parks in such a way that the heat passes through the ground into the groundwater. In Berlin alone, enough energy is transferred to the groundwater to supply 14,660 households with heat. According to the researchers, this warming could have long-term effects on groundwater quality. In their study, they also propose a solution. Using geothermal energy and heat pumps, the heat could be extracted from the ground and utilized.
