Multivalent Hygrothermal Material System for Double-Skin Envelope Dehumidification Cooling and Daylighting

Apr 16, 2018

Please note: The attached file below contains a paper from the BEST5 conference that is linked to a conference presentation in pdf format. Open with Adobe Acrobat for best results.

A unique paradox exists between the early and modern architectural and mechanical means of dealing with humidity in and around buildings. Traditional architectural conditions of biopolymeric thatch dwellings accommodated human thermal comfort through dehumidification by the materials employed at the building envelope. Original mechanical developments for dehumidification processes were developed specifically for removing moisture from materials in industrial applications. However, today, the modes by which humidity is treated for human comfort and material protection is inverted: buildings now utilize mechanical conditioning for dehumidification cooling functions and moisture protective materials in the building enclosure systems.

Emerging multivalent hydrophilic materials are able to process humidity and moisture transport in new ways to allow for a systemic return to dehumidification cooling functions integrated in the building envelope system. The hydrophilic polymers are synthesized with low energy methods and poured into molds and then lyophilized to create macroporous networks that enhance both the sorption and thermal characteristics in the proposed application. The thermal and optical properties of novel hygrothermal materials are identified and used as inputs for simulation modeling for the proposed multivalent building enclosure system. The initial results provide improvements on annual energy loads and consumption for hot-humid climate conditions (Miami and Mumbai).

The introduction of a sorption coefficient for the dehumidification function provides a unique contribution to design and performance analyses of double-skin envelopes. In addition, the dynamic modeling for temporal variations of material properties at the envelope also provides a new contribution to the field of building performance simulation. The challenges of these novel modes for moisture processing in the building envelope materials are addressed, with future work required for microbial identification and monitoring. The advantages from initial analytical and simulation modeling convey improvements for building energy conservation, natural daylighting, and water recuperation potential.

Aletheia Ida, PhD, assistant professor, school of architecture, U of Arizona, Tuscon
Published & professionally reviewed by: 
BEST5 Technical Committee

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