Nanotechnology-enhanced 4D-printed hydromorphic façade system for adaptive building envelopes: Design, simulation and prototype validation

Abstract

In large buildings are very heavy consumers of energy, large measure is a result of their HVAC systems. Traditional building envelopes don't react to change those results in excessive energy use. This study introduces a nano tech enabled 4D printed bio inspired hydromorphic facade which is able to independently react to changes in environmental humidity. From the pine cone’s bi-layer hydromorphic structure, drew inspiration for our façade is designed using computational tools, FEA, additive manufacturing and in to the use of nanostructured smart materials that improves moisture response and structural performance. In the active layer, cellulose acetate which reinforced with nanocellulose fibers, also in the passive layer we used moisture resistant PLA to create a programmable bi layer actuator. In humid conditions, an average 15% increase in curvature which the finite element simulation predicted – at the same time our prototype testing reported a reversible change of almost 12% that supported the computer model’s results. Also, we note that the model did a very good job in its prediction. Nanocellulose incorporation greatly improves mechanical stiffness, moisture diffusion, dimensional stability and response speed in traditional cellulose-based systems. Proposed is a design of a smart façade which does away with the need for sensors, motors, or external energy input in order to perform solar shading and natural ventilation thus it reduces the role of HVAC and at the same time improves energy performance of the building. In the integration of nanotech with 4D printing, a very promising direction that towards the development of smart, sustainable and self-adaptive building envelopes that is to say at the future of green architecture.