THERMAL INSULATION dissipation, passive gains or seasonal heat release become more beneficial, as illustrated in Figure 2. At a fundamental level, this adaptive behaviour is achieved by influencing the main modes of heat transfer within the envelope, primarily conduction and convection, and in some cases radia- tion. Depending on the system, this may occur through switching between a high-resistance mode, where heat flow is minimized, and a low-resistance mode, where heat transfer is allowed more readily or through a more gradual varia- tion in performance. Another important aspect of dynamic insulation is control. Some systems rely largely on passive material behav- iour, while others depend on active operation, such as moving components, airflow management or predefined switching logic. In both cases, the effec- tiveness of the system depends not only on the mechanism itself, but also on when and how that mechanism responds. REPRESENTATIVE DYNAMIC INSULATION MECHANISMS Dynamic insulation has been explored through a wide range of mechanisms and can be classified in several ways, including by heat-transfer mode, energy input, control approach, climatic suitability or switching range. For the purposes of this article, however, three representative examples are sufficient to illustrate the broader idea: movable or reconfigurable systems, airflow-based systems and phase-change material systems. • Movable or reconfigurable systems are among the most intuitive forms of dynamic insulation and have long appeared in buildings through adjustable elements such as shutters and other operable insu- lating layers. Their thermal behav- iour changes by physically reposi- tioning part of the assembly so that it alternates between a more insu- lating state and a more conductive one. As an example of these systems, Figure 3(a) shows a rotating mecha- nism in which the elements align to restrict heat flow in the insulated mode, whereas rotation opens a more direct heat-transfer path in the conductive mode. Their main advantage is the clarity and strength of the switching concept; although practical performance depends on reliable operation, whether manual or automated, and on the durability of moving components. • Airflow-based systems modify thermal performance by directing air through or along the wall assembly, allowing the envelope to act as both an insulating layer and a heat-exchange medium. In Figure 3(b), two common approaches are illustrated: parietodynamic systems, where air moves through dedicated channels within the wall, and permeodynamic systems, where air passes through a porous or air-permeable layer. In both cases, controlled airflow changes the convective heat exchange within the envelope and therefore alters its effective thermal resistance. Their appeal lies in the ability to integrate insulation and thermal regulation within the same assembly, though performance depends on airflow control, operating energy, airtight- ness and careful enclosure design. • Phase-change material systems, shown in Figure 3(c), rely on latent heat storage rather than mechanical movement or airflow. As the mate- rial changes phase between solid and liquid states, it absorbs and FIGURE 2: CONCEPTUAL ILLUSTRATION OF DYNAMIC INSULATION, SHOWING HOW THE BUILDING ENVELOPE CAN OPERATE AT DIFFERENT R-VALUES ACROSS WINTER, HOT SUMMER CONDITIONS AND COOLER NIGHT PERIODS. SPRING/SUMMER 2026 17
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