Characterisation of wood hygromorphic panels for relative humidity passive control

The need for the reduction of energy use has recently led to the development of expensive and technological smart materials. The exploitation of specific properties of natural materials can reduce both the economic and the environmental impact characterizing the new technologies. In this paper, the hygroscopic behaviour of wood, always considered as a negative property of the material for its end-use, becomes a positive feature in the realization of double-layered composites which passively react to the variations in relative humidity. The bending reaction of the wood bilayer is investigated and applied to a passive ventilation system for indoor environments, where the changes in relative humidity produce a controlled adaptation of the panels, contributing to reach an adaptive hygrothermal comfort.