Environmentally responsive building components: hydrogel-based material system

In conventional architecture, materials are generally static and they stay unchanged throughout the lifecycle of a building. Achieving indoor comfort often demands considerable energy use. In contrast, materials based on hydrogels provide benefits for creating responsive and sustainable architectural geometries, due to their responsiveness to environmental changes, including temperature and humidity. This study seeks to create a material-centric structure for designing responsive surface systems by investigating the swelling, shrinkage, and morphological characteristics of hydrogel formulations. Architectural capabilities of hydrogels are assessed through prototype-scale implementations as passive systems driven by intrinsic material responses to environmental conditions. The research adopts a reproducible approach that combines physical experiments, computational modelling, and multi-scale prototyping to examine the properties of hydrogel formulations made from sodium polyacrylate, sodium alginate, gelatin, and calcium chloride. Three hydrogel formulations were initially prepared as part of a material screening process. The first formulation was used as a baseline to observe maximum swelling behaviour, while two structurally more stable formulations were selected for further quantitative assessment through wetting–drying, dimensional stability, load-response, and prototype monitoring tests. The research presents a methodology that integrates material experimentation, parametric modelling, digital fabrication, and environmental monitoring that supports the development of a climate-responsive and resource-efficient architectural system. Within this framework, a conceptual modular system, HydroBrick prototype, was developed to investigate how hydrogel-based bricks can function as self-regulating cooling elements in an architectural context. A sequential prototyping process progressing from material samples to a 1:5 scale model and a full-scale installation enabled comparison across multiple scales. The tests showed that hydrogel performance depends not only on water uptake capacity, but also on dimensional stability, drying behaviour, and structural support. Seven-day monitoring of the 1:5 prototype demonstrated measurable localized cooling effects relative to the timber-only control system, with different response patterns observed between the two material formulations. The full-scale pavilion further indicated temporary microclimatic cooling effects near hydrated hydrogel surfaces, demonstrating the potential of hydrogel-based assemblies to support localized passive comfort under real indoor exhibition conditions.