Decarbonising well-insulated buildings in a warming climate: The case of adaptive thermal comfort with geothermal space heating

Buildings contribute to 40% of global energy demand and are responsible for a third of CO2 emissions. Strategies to decarbonise buildings are, therefore, crucial for reaching the net-zero emissions targets by most of the countries in the world. This study investigates the feasibility of decarbonising well-insulated buildings with current and future weather scenarios by applying adaptive thermal comfort strategy in combination with a closed-loop deep geothermal system. An office building has been chosen as a case study because of the comprehensive sensor system installed in the building which allows for detailed data extraction and analysis. The results show that the building's heating and cooling demand can be reduced by 51% using an adaptive thermal comfort approach, while this decreases to 45% in 2080 under a warming climate. Combined with this adaptive approach, geothermal energy can satisfy 50% of building heating demand at present when combined with intermittent storage scenarios, while 5 deep borehole heat exchangers (DBHEs) would be required to meet all the heating demand directly. In conclusion, this study shows that using a DBHE and adaptive thermal comfort approach to well-insulated buildings presents an innovative and low-cost opportunity for buildings to significantly lower building thermal demand and carbon emissions.