Numerical Investigation of Thermally Activated Building Structures (TABS) Controlled by a Switchable Insulation Panel

Abstract

Electrifying heat generation in existing buildings in Germany presents a promising pathway toward more sustainable energy use. This thesis investigates an innovative electric heating and storage system that utilities the inherent thermal mass of concrete layers in solid storey ceilings. By thermally activating these layers and controlling heat transfer via a switchable insulation panel, the system transforms existing ceilings into dynamic thermal storage units. The objective was to develop an operating strategy capable of meeting the fluctuating heating demands of a reference building while leveraging the storage capacity to avoid high electricity price periods. A preliminary study introduced a static insulation layer to ensure compliance with standards for ceiling heating systems. Subsequent analyses, conducted through one-dimensional simulations in COMSOL Multiphysics®, enabled the development of a controller that adjusts the ceiling heat flux by modulating the thermal conductivity of the switchable insulation. During charging, the system stores heat efficiently while limiting thermal losses to the room; during discharging, it enables targeted heat delivery. A combined cyclic operating strategy was designed that fully covers the heating load, despite the heating mat being activated only intermittently and exclusively during periods of low electricity prices. The results demonstrate that the system fulfils all relevant standards and can function as a standalone heating solution. Future research should investigate optimized system configurations and the integration of predictive control.