Use of air-to-air heat pumps for air conditioning in existing buildings: impact of building thermal mass on consumptions and comfort levels
The decarbonisation of the building sector is a central priority in European energy policy, as buildings account for about 40% of total energy consumption. In this framework, the residential sector plays a key role in this transition, with multi-family buildings representing a significant portion of housing. In these buildings, constraints on space and technical integration often make the use of thermal storage impracticable. To this aim, this study investigates the potential of exploiting building thermal mass to enhance the performance of air-to-air heat pumps in existing residential buildings, with specific focus on the winter heating operation mode. A building–heating system model was developed and validated, and an advanced control strategy was implemented to use structural thermal mass as a storage in a multi-family case-study building. Three construction clusters and multiple wall heat-capacity enhancement levels were compared against a baseline to assess the effects on energy consumption and thermal comfort. Results show energy-consumption reductions of up to 20% in the highest-capacity configuration, with favourable comfort outcomes during occupied hours. These findings indicate that the thermal mass of buildings can support more efficient heat-pump operation, offering a cost-effective solution for existing buildings