Re-thinking Indoor Humidity Control Strategies: The potential of additive manufacturing with low-carbon, super hygroscopic materials.

Abstract

Indoor humidity plays a major role in our comfort and well-being. For this reason, mechanical systems are often used to regulate indoor humidity levels, a choice that can entail relevant embodied and operational carbon emissions. This study offers an alternative solution: using materials that naturally buffer moisture to passively regulate indoor humidity levels. In this work, a geopolymer composite incorporating industrial waste is implemented via a binder jet 3D-printing technology. The combination of the super hygroscopic nature of the material and optimal geometry allows for an effective reduction of embodied emissions and unlocks an unprecedented potential for passive regulation of indoor humidity. Results show that the adoption of 3D-printed geopolymer-based tiles can improve the annual indoor hygrometric conditions by up to 90% in a library hosting 15 people: a passive performance that is inconceivable to obtain with conventional building materials and manufacturing methods. The 3D-printing technology allows for optimal usage of material and consequent lower embodied emissions. In the case study considered, the environmental impact of using 3D-printed tiles emerges to be lower than adopting a conventional dehumidification system to actively achieve equivalent indoor hygrometric comfort levels over a 15-year time span. The outcomes of this study pave the way towards merging super hygroscopic low carbon materials with the advanced manufacturing technique of binder jetting in order to regulate indoor humidity levels and reduce indoor environments' dependency on mechanical systems.

Hygroscopicity and Morphology of Bio-Based Boards—The Influence of the Formulation

“…As hazelnut-shell-based and A. donax-based boards have demonstrated interesting hygroscopic behavior [29,30], which can be useful to passively contribute to indoor comfort [50], reducing energy consumption [51], the present study mainly considered this property. The contribution of each material was investigated by testing them individually and in composites.…”