Fig. 5

Upper (map a) and lower (map b) thermal boundary condition (Dirichlet) implemented into the numerical model. The upper thermal boundary condition shows a variable mean annual surface temperature over the last 30 years (DWD 2013). The lower thermal boundary condition shows the temperature distribution extracted from the 3D lithospheric-scale conductive thermal model of Przybycin et al. (2015b). The upper figure additionally shows the prescribed lateral hydraulic boundary conditions (modified after Frisch and Huber 2000). 20 locations of the geothermal energy production sites are shown for which observed temperatures are available. Our predicted temperatures have been compared to these observations. The residual temperature (calculated–measured) is given. The temperature difference between calculated and measured values is additionally given for the coupled and conductive case in Table 2