Tuning the Solar Performance of Building Facades through Polymer 3D Printing: Towards Bespoke Thermo-optical Properties

Abstract

Façades are the primary interface controlling the flow of solar energy in buildings and affecting their energy balance and environmental impact. Recently, large-scale 3D printing(3DP) of translucent polymers has been explored as a technique for fabricating façade components with bespoke properties. Transmissivity is essential for facades, as the response to solar radiation is crucial to obtaining comfort and significantly affects electricity and cooling demands. However, it is still unclear how 3DP parameters affect the optical properties of translucent polymers. This study establishes an experimental procedure to relate the optical properties of PETG components to design and 3DP parameters. We observe that printing parameters significantly affect layer deposition, which governs internal light scattering in the layers and overall light transmission. Moreover, the layer resolution determines angle-dependent properties. We show that printing parameters can be tuned to obtain tailored properties, from high normal transparency (~90%) to translucency (~60%) and with a range of haze levels (~55- 97%). These findings present an opportunity for large-scale 3DP of bespoke façades, which can selectively admit or block solar radiation and provide uniform daylighting of a space. In the context of the building sector decarbonisation, such components hold great potential for reducing emissions while ensuring occupant comfort.