Design Proposal
Purpose Statement
Through the integration of an ETFE cushion façade system and a microalgae photobioreactor, microalgae can simultaneously serve as a dynamic shading device as well as a sequestrator of carbon.
Research Question:
Can the inner foil of a tri-layer ETFE pillow be reinforced to substantially reduce deflection through the addition of plastic tensile members?
Through the integration of an ETFE cushion façade system and a microalgae photobioreactor, microalgae can simultaneously serve as a dynamic shading device as well as a sequestrator of carbon.
Research Question:
Can the inner foil of a tri-layer ETFE pillow be reinforced to substantially reduce deflection through the addition of plastic tensile members?
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Literature Review
Though ample and extensive research has been conducted on numerous subtopics relating to both ETFE (ethylene-tetrafluoroethylene) foil and microalgae, this researcher has found little literature directly relating to the deflection of ETFE foil as a result of an inequality of density on either side (ie. air and water). The following review sought to analyze topics that were as relevant as possible to the researchers own research question.
Kheybari and Lam in their paper Building Envelope as Heat Generator – The impact of Water-filled ETFE Cushion on Energy saving and Comfort explored the feasibility and effects of incorporating a water bladder into an ETFE cushion. Their genesis was to conceive the relationship between water and the building as blood and the body. They hypothesized that such a water integrated ETFE cushion could regulate heat gain or loss.
Though ample and extensive research has been conducted on numerous subtopics relating to both ETFE (ethylene-tetrafluoroethylene) foil and microalgae, this researcher has found little literature directly relating to the deflection of ETFE foil as a result of an inequality of density on either side (ie. air and water). The following review sought to analyze topics that were as relevant as possible to the researchers own research question.
Kheybari and Lam in their paper Building Envelope as Heat Generator – The impact of Water-filled ETFE Cushion on Energy saving and Comfort explored the feasibility and effects of incorporating a water bladder into an ETFE cushion. Their genesis was to conceive the relationship between water and the building as blood and the body. They hypothesized that such a water integrated ETFE cushion could regulate heat gain or loss.
“Conceptual control system: the idea of building’s “Blood Circulation”, and integrated multi-functional façade components”
Their study utilized digital modelling software to perform daylight analysis (Radiance and Daysim) as well as thermal simulations (Trnsys18). They were able to confirm that their system successfully reduced cooling loads through lowering the Solar Heat Gain Coefficient (acheived by “absorbing solar radiation in water flow with a constant mass flow rate and rejecting the heat to the soil or by radiating to the cold sky during summer night”), harvest solar heat, maximize daylight utilization, as well as improve thermal and visual comfort levels.
This study illustrates a primary capability of ETFE necessary to proceed with the microalgae integrated ETFE facade research - that ETFE foil is capable of holding liquid material. Furthermore, it proves the feasibility of housing both air and liquid in adjacent chambers within the same ETFE pillow.
Their study utilized digital modelling software to perform daylight analysis (Radiance and Daysim) as well as thermal simulations (Trnsys18). They were able to confirm that their system successfully reduced cooling loads through lowering the Solar Heat Gain Coefficient (acheived by “absorbing solar radiation in water flow with a constant mass flow rate and rejecting the heat to the soil or by radiating to the cold sky during summer night”), harvest solar heat, maximize daylight utilization, as well as improve thermal and visual comfort levels.
This study illustrates a primary capability of ETFE necessary to proceed with the microalgae integrated ETFE facade research - that ETFE foil is capable of holding liquid material. Furthermore, it proves the feasibility of housing both air and liquid in adjacent chambers within the same ETFE pillow.
“The Schematic of the basic operation of envelope components; dynamic thermal and optical properties in summer: Left: Summer night (SN), Right: Summer day (SD)”
Through their illustrations (see above), Kheybari and Lam showed an anticipation of deflection in the ETFE water bladder. This highlights the need for an innovation addressing such deflection. Perhaps through reinforcing the interior ETFE foil and increasing the atmospheric pressure within the air chamber, the liquid portion would be held in a more rigid form against the exterior foil and cause less deflection to both the middle and exterior foils.
Robinson’s exploration of the Structural Opportunities of ETFE provide significant foundational knowledge about the capabilities and limitations of ETFE foils, particularly as it relates to ETFE cushions.
The author highlights the mechanical requirements for the inflation system, explaining that “one or more inflation units are required to maintain the pressure of the cushions [per] 1000 m2 area”. It is also noted that the air pressure within the cushion is typically held between 200-750 Pa, which is the equivalent of approximately 0.029-0.109 psi.
Also covered in depth in this research are the strength properties of the ETFE foil. The break strength is 50 N/mm2 or about 7250 psi.
These key insights related to pressure provide a foundational framework to expand upon when increasing the pressure within the air chamber to suspend the microalgae and medium evenly within its chamber.
Pires, et al. elaborates on the conditions for optimal algae growth within a closed system. Their research provides us with an understanding of the relationship between illumination and volume within a photobioreactor.
Through their illustrations (see above), Kheybari and Lam showed an anticipation of deflection in the ETFE water bladder. This highlights the need for an innovation addressing such deflection. Perhaps through reinforcing the interior ETFE foil and increasing the atmospheric pressure within the air chamber, the liquid portion would be held in a more rigid form against the exterior foil and cause less deflection to both the middle and exterior foils.
Robinson’s exploration of the Structural Opportunities of ETFE provide significant foundational knowledge about the capabilities and limitations of ETFE foils, particularly as it relates to ETFE cushions.
The author highlights the mechanical requirements for the inflation system, explaining that “one or more inflation units are required to maintain the pressure of the cushions [per] 1000 m2 area”. It is also noted that the air pressure within the cushion is typically held between 200-750 Pa, which is the equivalent of approximately 0.029-0.109 psi.
Also covered in depth in this research are the strength properties of the ETFE foil. The break strength is 50 N/mm2 or about 7250 psi.
These key insights related to pressure provide a foundational framework to expand upon when increasing the pressure within the air chamber to suspend the microalgae and medium evenly within its chamber.
Pires, et al. elaborates on the conditions for optimal algae growth within a closed system. Their research provides us with an understanding of the relationship between illumination and volume within a photobioreactor.
Their study illustrates the need for a successful negation of deflection within an ETFE cushion. Such a negation would evenly disperse the algae across the surface area of the exterior foil, creating a consistent thickness of algae - this in turn would shift the ratio of luminosity to volume in favor of optimal algae growth.
Mockup
Describe process, fabrication methods (include photos), plan for completion (list of materials, supplies, budget, etc). electronic controls strategy. You should be able to get actual data from this mockup. Be sure to caption all photos.