Design, Additive Fabrication, and Prototype Validation of 3D-Printed PETG Microalgal Curtain- Wall Modules with Embedded Control

Abstract Building-integrated photobioreactors require façade components that reconcile geometric adaptability, manufacturability, liquid containment, modularity, and operational monitoring. This study develops a 3D-printed PETG microalgal curtain-wall module integrating parametric design, additive fabrication, embedded sensing, and prototype operation. Nine Rhino/Grasshopper-generated variants (150 × 150 mm) exhibited closed-mesh areas of 707.0–729.4 cm² and predicted filament demand of 29.75–30.54 g (CV 0.87%). Recorded printing times ranged from 100 to 125 min (CV 7.87%). A continuous single-wall spiral-vase strategy enabled transparent reactor prototypes for liquid filling and circulation. An STM32-based system provided multi-source sensing and rule-based pump actuation. Prototype tests showed liquid containment, pump-driven circulation with Spirulina (Arthrospira) culture medium, and preliminary multi-module assembly. The results establish the prototype-level building-engineering feasibility of additively manufactured bio-reactive curtain-wall modules while identifying the requirements for future façade-scale performance validation.