Experimental study on the thermal behavior of a novel wall structure composed of different layers to improve the store and supply capabilities of the wall

The European Union’s climate goals and the Green Deal emphasize increasing renewable energy shares and enhancing energy efficiency across all sectors. In Europe, approximately 78 % of the energy consumed by households is utilized for hot water and space heating, with the building's thermal envelope playing a crucial role in managing thermal comfort and their energy consumption. To address these challenges, a switchable thermal insulation (SWTI) with adjustable thermal conductivity has been developed. This innovative component, tested under laboratory conditions, enhances both energy storage and heating performance by dynamically adjusting its properties based on environmental conditions. The SWTI is a core component of a novel Multi-Layer Wall (MLW) designed to maximize the utilization of renewable energies and improve energy transfer within buildings. This wall structure has been incorporated into the 'SmallHouse IV' demonstrator for real-world testing. The experimental analysis focuses on the decrement factor, thermal lag, and overall energy performance of the wall, comparing it with traditional insulated walls. Initial results indicate that the SWTI increases the thermal storage capacity of the wall by 63 % and heating capability by 102 %, thereby ensuring thermal comfort and maintaining appropriate surface temperatures. However, in a single-family house in the Central European climate (SFH 30), the technology showed limited additional benefits during the heating season due to the scarcity of excess on-site heat. This underscores the climate-dependent effectiveness of the SWTI layer, suggesting it is more suited to environments with consistent external or high temperature heat sources. • Novel wall with Switchable Thermal Insulation (SWTI) extends energy storage up to 500 hours. • 37% heating efficiency improvement, enhancing energy use during colder periods. • 13.3% better thermal time lag; decrement factor reduced to 0.001 via dynamic SWTI control. • Limited use in well-insulated European buildings due to lack of excess heat. • Suitable for industrial sites or areas with steady external heat sources.