In urban areas, replacing heating systems with heat pumps can be difficult due to space constraints and approval hurdles. In existing buildings in particular, traditional heat sources such as air or geothermal probes are often not feasible due to the density of the settlement. The concept proposed in the project uses the ground directly beneath buildings as seasonal heat storage. Short vertical boreholes are drilled from the basement and either short geothermal probes or heat pipes are installed. Two variants of this thermal activation are being investigated: using an activated floor slab with heat pipes or exclusively using short geothermal probes. Regeneration in summer is achieved, for example, through free cooling, active cooling (air conditioning), recoolers, or solar heat. Modern drilling technologies also enable implementation in existing buildings. The aim of the project is to demonstrate how ground-coupled heat pump systems can be efficiently implemented in different types of buildings.