RESPIRE: Passive, Responsive, Variable Porosity Building Skins 

Buildings require heating and/or cooling, along with provision of fresh air to prevent damp and maintain a healthy internal environment, resulting in significant energy input and associated carbon emissions. Current best practice is to provide high levels of insulation and airtightness. However, this approach requires mechanical ventilation and control systems to work effectively. Providing suitable ventilation without these systems would reduce the cost, complexity and emissions in the construction, operation and maintenance of buildings. It would also increase occupant comfort and internal air quality by reducing levels of carbon dioxide and pathogens including the coronavirus.

The project proposes to use moisture-responsive materials in combination with insulation to produce building skins that allow variable levels of ventilation, depending on the humidity of the environment inside and outside the building. For example, if the inside of the building is humid, pores will open in the skin, increasing airflow. Alternatively, if the outside of the building is moist, pores will close, keeping the internal environment dry. With careful placement of these skins around a building, comfortable internal conditions can be maintained, with no ongoing carbon emissions.

RESPIRE will take advantage of the natural moisture-responsiveness of some abundant organic materials. Wood, hydrogel (made from seaweed), wool and flax fibres all swell and shrink in response to varying levels of moisture and these can potentially be used to produce novel breathing building skins with low cost and environmental impact. We will also explore the moisture responsive behaviour of biomaterials including mycelium and bacterial cellulose.