Development of a novel thermal insulation system for building envelope application
E. Katsoula (TU Delft - Civil Engineering & Geosciences)
M. Bilow – Mentor (TU Delft - Architecture and the Built Environment)
M. Overend – Mentor (TU Delft - Architecture and the Built Environment)
M.A. Popescu – Mentor (TU Delft - Civil Engineering & Geosciences)
Rowan van Wely – Mentor
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Abstract
The building sector is responsible for 38% of global energy and process-related greenhouse gas emissions. In recent decades, a rapid increase in energy consumption in buildings has been observed, making energy reduction a pressing issue. Thermal insulation systems that can operate dynamically by alternating between conductive and insulated states are gaining attention in architectural applications, as they can reduce energy consumption while improving occupants’ comfort levels.
Despite research into adaptive insulation technologies, none are currently implemented in real-world buildings. The aim of this thesis is therefore to identify the reasons for this and explore possible ways to design an adaptive insulation system. As no established standards exist, the research first defines design criteria related to thermal performance, feasibility, and technological complexity.
A design space was developed considering core geometry, outer layer mobility, cavity compartments, actuation type, and switching mechanisms between thermal states. From this, six concepts were developed based on an inflatable and compressible structure that transitions between insulating and conductive states.
The core geometries were modelled in TRISCO steady-state 3D software, where parameters were tested to optimise thermal performance. The goal was to achieve thermal resistance comparable to state-of-the-art insulation in the insulated state and a significantly lower resistance in the conductive state, comparable to an uninsulated concrete block.
Thermal transmittance (U-value) was calculated numerically and validated using analytical models. Results show that air cavity thickness and membrane emissivity strongly influence thermal resistance. The degree of evacuation of the cavity significantly affects the range of thermal switching. Systems allowing full compression of the core achieve the lowest resistance governed by solid conduction.
One concept met the design goal, achieving thermal transmittance values ranging from 0.13 W/m²K (insulated state) to 2.79 W/m²K (conductive state), corresponding to thermal resistances from 7.5 m²K/W to 0.4 m²K/W.
A multi-criteria analysis was used to select the final design, resulting in a 1.5 m by 0.75 m opaque panel with a low-emissivity honeycomb core. The panel thickness changes from 0.18 m in the insulated state to one-third when compressed. Actuation is achieved via a dual-function pump supplying air to internal channels.
The system operates reversibly between an inflated insulating state and a deflated conductive state. The façade integration allows the transition between thermal states to be visible.
This research demonstrates the potential of adaptive insulation systems based on controllable heat transfer parameters. While simulation results are promising, experimental validation with physical prototypes is required, along with further refinement of the air-supply system design.