Researchers at the Institute for Advanced Architecture of Catalonia (IAAC) developed Water-Driven Breathing Skin, a breathing skin-like material that performs open-close behaviour to facilitate passive ventilation and cooling effect for outdoor spaces.

Homeostasis is the tendency of organisms to auto-regulate and maintain their internal environment in a stable state at which they are functioning optimally.

The IAAC research is based on the question whether a smart material system can function as these organic activities. The researchers were especially interested in breathing. The open/close behaviour enables air exchange and regulation in body temperature, which resembles that of ventilation.

The main material used for the system is sodium polyacrylate, a superabsorbent polymer in the hydromorph family. In a preliminary study, it turned out that the material could absorb up to 300 times its volume in water in a short time span. In addition, it prolongs the evaporation process, and therefore the effect of evaporative cooling.

The study also tested how compositing and encapsulating using elastic fabrics affected the sodium polyacrylate, as well as which shape, pattern and size would optimise the open/close mechanism for passive ventilation and cooling in hot and dry summer climates.

As the targeted climates have a lack of water, the system is designed to collect fog and dew. It is 15 times more water-efficient than commonly used misting systems.

The Water-Driven Breathing Skin is developed as a semi-passive system for outdoor spaces in hot climates. The system is cost-effective in construction and maintenance, as well as energy-efficient for areas with water shortage yet also tensile and liable for urban spaces.

Photos: IAAC