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This research introduces a novel lyophilized hydrogel for double-skin envelope (DSE) integration as a dynamic louver system to provide dehumidification of moisture, daylighting modulation, and recuperation of water condensate. The work links empirical experiments for thermal, optical, and sorption properties of the hygrothermal materials alongside system scale analytical models to inform energy and water conservation measures. The system scale analyses are conducted with LBNL WINDOW7 in combination with numerical analytical models, in addition to select computational fluid dynamic (CFD) studies for development of louver geometries to optimize sorption effectiveness in the DSE cavity airstream. Effective heat transfer and visible transmittance values for the dynamic states of the DSE hygrothermal louver system are then linked to building scale analyses in the Rhino- Grasshopper platform using the Honeybee plug-in to run EnergyPlus. The dynamic state envelope system is assessed through annual integration modeling for hothumid climate conditions. The work introduces new aspects in simulation modeling with integration of the standard mechanical air-handling system functions to be coupled with multi-state dynamic properties for the envelope system in building scale analyses. A sorption coefficient is identified for analytical modeling of the DSE hygrothermal louver cavity thermodynamics. The work also integrates a new calculation tool in the simulation platform for evaluating potential water recuperation
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Multivalent Hygrothermal Material System for Double-Skin Envelope Dehumidification Cooling and Daylighting
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.
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- Award ID(s):
- 1650671
- PAR ID:
- 10080788
- Date Published:
- Journal Name:
- Building Enclosure Science and Technology Conference
- ISSN:
- 2166-9074
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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