Dynamic assessment of buildings’ thermal footprints on subsurface temperature regimes in urban environments

Source abstract

A better understanding of temperature changes in the urban subsurface is becoming increasingly important in light of the growing subsurface utilization, particularly in urban areas. While major subsurface heat sources have been identified and numerous studies have defined ranges for various anthropogenic heat inputs, there is still a lack of a comprehensive approach that enables the reliable prediction of heat emissions from buildings, ranging from individual structures to entire urban quarters, while taking into account local geological and hydrogeological conditions, as well as a heterogeneous building stock and its temporal evolution. Therefore, this study introduces an innovative model-based workflow for assessing the thermal footprints of buildings by integrating the findings of building physics simulations, aerial imagery, and GIS analysis into dynamic heat and groundwater modeling. The workflow is subsequently tested in detail through a case study of a residential peri-urban quarter. Results of our case study analysis show that the impact of building heat release is still observable in more than 15 m depth below individual buildings, depending on the building properties. The superposition of thermal effects from individual buildings may collectively influence groundwater at depths exceeding 25 meters. In addition to predicting subsurface temperature changes caused by buildings, the developed approach also facilitates the disentangling of combined anthropogenic temperature signals. As demonstrated in our study, the developed approach enables not only the prediction of thermal inputs from buildings but also the precise quantification of the impact of intensive shallow geothermal energy use on groundwater temperatures.