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

Facades 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 facade components with bespoke properties and functionalities. Transmissivity is essential for building facades, as the response to solar radiation is crucial to obtaining comfort and greatly 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. It is observed that printing parameters control layer deposition, which governs internal light scattering in the layers and overall light transmission. Moreover, the layer resolution determines angle-dependent properties. It is shown that printing parameters can be tuned to obtain tailored optical properties, from high normal transparency (approximate to 90%) to translucency (approximate to 60%), and with a range of haze levels (approximate to 55-97%). These findings present an opportunity for large-scale 3DP of bespoke facades, which can selectively admit or block solar radiation and provide uniform daylighting of a space. In the context of the building sector decarbonization, such components hold great potential for reducing emissions while ensuring occupant comfort.