Geothermal energy at different depths for district heating and cooling of existing and future building stock

Recent developments in the building sector, district heating and cooling (DHC) field, and geothermal technology are reported here, which indicate the trends and efforts to more sustainable and climate-friendly heating and cooling supply systems and may provide guidance for policymakers and decision-makers. The tendency towards lower temperatures in district heating networks and higher building envelope requirements are identified. Meanwhile, technologies have been developed in the geothermal sector to reach deeper subsurface layers and to extract heat with higher temperature. To follow the progress in the building sector and DHC, multi-faceted geothermal systems are considered here, which include components of deep, medium-deep and shallow geothermal resources. Because different temperatures occur at different depths, such a system can be used for different generations of DHC and buildings. This concept may be a part of an energy hub, and can help facilitate transformation from fossil fuel-based DHC to geothermal-based DHC. The concept of multi-faceted geothermal system is presented, its SWOT analysis is performed and further research directions are identified.