Dynamic Faรงade Prototype Jericho Bankston Department of Architecture 1206 University of Oregon Eugene, OR 97403 jerichob@uoregon.edu
Cameron Ewing Department of Architecture 1206 University of Oregon Eugene, OR 97403 camerone@uoregon.edu
Ihab Elzeyadi, Ph.D., FEIA, LEEDAP Supporting Faculty, Associate Professor Department of Architecture 1206 University of Oregon Eugene, OR 97403 ihab@uoregon.edu ABSTRACT This paper describes and analyzes the performance of a dynamic shading device designed to increase occupant comfort in a typical commercial building. The study of the dynamic shading device is done through Integrated Environmental Solutions Virtual Environment (IESVE) software. This software is used to realize the simulations for daylighting, solar heat gain, glare analysis and sun shading capabilities. Bee or Building for Environmental and Economic Sustainability software is used to analyze the sustainability and environmental impact of the various materials used. A real prototype is then developed to test the shading devices performance on the Faรงade Integrated Technologies (FIT) Facilities at the University of Oregon. INTRODUCTION A dynamic shading device does more than just reduce solar heat gain and glare issues in a particular space. A dynamic shading device increases occupant comfort levels and creates better interior building conditions while reducing building electrical loads. While the most efficient shading devices tend to have automated operation it limits user
control and comfort focusing only on building performance issues. Other shading devices allow user operation but fail to meet building needs or perform to their full capabilities due to the users failing to adjust the device when necessary. Operable devices also increase maintenance and tend to fail more leaving the building vulnerable. The focus for this dynamic shading device was to create a stationary device that met or exceeded the needs of a Pacific Northwest building and increase occupant comfort. The concept for the device considered Transparency, Light, Glare, Shade, Air, Material, Detail, Depth and user Comfort. This paper looks at how all these variables can be integrated into a high performance and dynamic shading device system to help improve building occupant conditions. NOMENCLATURE Eco-Resin: is a proprietary translucent, copolyester sheet material that contains a significant amount of recycled content but also retains its core physical properties. (Source: http://ecorealty.blogspot.com/2006/06/ecore sin.html)
Visible Transmittance (Tvis): is the amount of light in the visible portion of the spectrum that passes through a glazing material. (source: http://www.commercialwindows.org/vt.php)
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Daylight Factor: is the ratio of the light level inside a structure to the light level outside the structure. (source: https://en.wikipedia.org/wiki/Daylight_factor)
Illuminance: is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate with human brightness perception.
The design prototype will be installed on the south oriented Façade integrated Technologies (FIT) Facility at the University of Oregon. The test bay is 6 feet high by 4 feet wide. The prototype will be tested for two weeks and will be monitoring solar radiation, glass surface temperatures and illuminance values during varying weather conditions in Eugene, OR. The prototype is installed in the bay marked “Piano” as illustrated by Figure 2.
(source: https://en.wikipedia.org/wiki/Illuminance)
Luminance: how much luminous power will be detected by an eye looking at the surface from a particular angle of view. Luminance is thus an indicator of how bright the surface will appear. (source: https://en.wikipedia.org/wiki/Luminance)
Glare: is caused by a significant ratio of luminance between the task (that which is being looked at) and the glare source. Factors such as the angle between the task and the glare source and eye adaptation have significant impacts on the experience of glare. (source: https://en.wikipedia.org/wiki/Glare_(vision))
PROTOTYPE DESIGN Design Context: In this study the design and prototype is based off of a typical single sided office bay. This bay is 20 feet wide and 30 feet deep with a finished floor to finished floor height of 14 feet. This includes the structure and mechanical equipment of the building. The office room is assumed to face south. Figure 1 illustrates the characteristics of the typical bay.
Figure 2: Elevation of FIT Facility Source: 507 High performance façade-HIPE Lab
Design Concept: a. Concepts & Precedents Throughout the design process it was determined the dynamic shading device should serve more than just enhancing the building but also enhance the occupants experience within the building both visually and through comfort. Focusing on three main ideas of design: 1) Eco-Aesthetic: Buildings tend to alienate themselves from the surroundings and are technologically organic and non-linear. They emphasize creating an entirely new ecological system that reconfigures our consciousness of nature. (source:http://blog.cpgcorp.com.sg/?p=1930)
2) Eco-Centric: Buildings classified as being eco-centric are fragile and harmonious with nature or rather look like nature. Technologies are off-thegrid and decentralized with no reliance on external sources. Figure 1: Typical Office Bay
(source:http://blog.cpgcorp.com.sg/?p=1930)
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3) Eco-Technic: The Eco-Technic paradigm treats space as being global and urban in nature. Buildings are intelligent, heavily reliant on technology and tend to look like the future. (source:http://blog.cpgcorp.com.sg/?p=1930)
These are selected as the foundation of the design for the prototype. While realizing the possibility of moving away from a technology based design was near impossible the idea behind the prototype was to maximize sustainability and only utilize technical products when the benefit outweighs the cost. This lead to an Eco-Centric design taking cues from nature and adapting them for building façade purposes. To remain open to design changes and adaptations there was no main precedent study, however the design and prototype took cues from a number of precedent images. These range from the Diphelleia Grayi or Skeleton Flower in Figure 3 to John Curtin College of the Arts in Figure 4.
Figure 4: John Curtin College of the Arts Source: http://www.pta.com.au/
All precedents were used as a way to inspire a unique shading device that could operate on a double façade building type. To reduce maintenance on the façade of the building the design goal was to limit the dynamic shading device to only the cavity between the double façade. This reduces wear on the shading device and also frees the office building façade. b. Design Characteristics To maximize daylighting and reduce glare and solar heat gain the façade is broken up into three pieces each with their own T-vis. The spandrel glass makes up the bottom portion of the façade and has a T-vis of 25%. The viewing portion of the façade has a T-vis of 60% and the clearstory has a T-vis of 70% to allow the maximum amount of daylight to penetrate the office bay. Figure 5 shows a section of how the façade is broken up.
Figure 3: Diphelleia Grayi "Skeleton Flower" Source:http://www.boredpanda.com/skeleton-flower-clearsee-through-rain-wet-diphylleia-grayi/
Figure 5: Section
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Lower Daylight Section: It was important to utilize a double façade not only for maintenance purposes but also as a means to trap outside air and heat it during cold months. A double façade also allows the building to have different levels of solar heat gain. Using a phase change glass with love Tvis in the spandrel region of the façade, roughly 25% of the over-all façade, the temperature inside the office building can be reduced during hotter portions of the year. During cooler portions the glass will change back and allow in more sunlight. Mid Daylight Section: The critical view portion of the façade was treated as an inaccessible extension of the office bay. The double façade allows for a sense of depth in the façade. A sustainable eco-resin made by 3Form is used in 2 separated layers. These layers reduce direct sunlight in while allowing a visual depth in the façade and a play of brilliance on the interior office space. (Figure 6)
ability for the device to be effective 100% of the time but also reduces the ability for human and mechanical error or damage. So the dynamic shading device was design to perform around the summer and winter solstice as well as the equinox to achieve maximum efficiency year round. The goal behind the design of the dynamic shading device was to create plays of brilliance on the interior of the office without causing glare. Similar to the plays of brilliance nature can create. (Figure 7)
Figure 7: Water Reflection Source: http://i.stack.imgur.com/lrOw7.jpg
METHODS Research Methods and Instruments:
Figure 6: 3-Form Eco Resin Source:https://s-media-cacheak0.pinimg.com/236x/16/b4/f9/16b4f99fed02aa32c8e9c470e 911fbc0.jpg
Upper Daylighting Section: The eco resin reduces interior glare for occupants while the light shelf above brings in daylighting to the office bay. The light shelf extends from between the double façade into the interior of the office space, well overhead it doesn’t interfere with interior movement but also acts as a shading device during and around the summer equinox when the sun is at its highest. To reduce user and mechanical error the shading device is stationary. This limits the
The design and research process utilized hand sketches, computer drafting, physical modeling and the IESVE software to analyze the dynamic shading device performance. Sketches and physical models allowed for the exploration of ideas without the complexity of buildability. By designing to enhance user experience and visual connection the dynamic shading device became more than a shading device but rather an integral part of the building envelope and occupant experience. Using IESVE after having designed a user experience allowed for the adjustment of elements rather than the design of solely a shading device. By optimizing for the different times of the year: March 21st, June 21st and
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December 21st tweaks were made to produce a well performing dynamic shading device. Performance Simulation: a. Daylighting For analysis clarification and diagram purposes all images mentioned are in the same format. That is that the control bay will always be on the far left. To get the IESVE software to work with a double faรงade building Test Bay one was modeled with the double faรงade and Test Bay 2 was modeled without the second facade. This is so that data can be accurately collected from the interior of the model.
Figure 8: Daylighting Factor
Figure 10: Suncast
The suncast shows that while the control bay does indeed receive more daylighting that lighting is far too intense for the space. The test bays reduce the excessive lighting while still allowing it to penetrate deep within the space providing all occupants with natural daylighting. b. Solar Control
Figure 11: Sun Angles
Figure 12: Solar Heat Gain Coefficient Figure 9: 2% Daylighting Factor
The daylighting factor shows minimal loss in adequate daylighting both in the overall factor as well as the 2% threshold diagrams. Figure 8 indicates that while Test Bay 2 loses brighter light deeper in the space the more intense light near the glazing is reduced.
Solar heat gain on the face of Test Bay 1 indicates that the glass is heating up significantly. This is beneficial because it means the air inside the space can heat up if required during cold months. Test Bay 2 while inaccurate due to the lack of the second faรงade is showing an initial solar heat reduction of 10%. While this is not optimal the analysis is missing the second faรงade which helps reduce solar heat gain drastically. It is also impossible to represent phase change glass in IESVE which is also contributing to a lack of heat gain Page | 5
reduction. So as a base analysis the 10% reduction can only increase. (Figure 12) c. Glare Analysis The glare of the typical office bay is drastically reduced with the dynamic shading device. While it is not entirely eliminated the source of glare at first glance is reduced by 50% in some areas. (Figures 13 & 14)
Figure 13: Control Bay Glare Analysis
exchange in summer and provides heat in the winter. In the summer, radiant heat will pass through the first layer of the façade and will be reflected by the Heat Mirror glazing of the second layer. This will allow the cavity to gain heat and create a low-pressure. zone. Cooler air from the vented atrium will flow through the office bays moving from high pressure to low pressure. In this scenario, inlets and outlets will be placed every four floors on the exterior and the interior will have open operable windows at the clerestory level. The Façade will act similarly in the winter, heating cooler air to a higher temperature within the façade layers. However, in this scenario the atrium will not be vented, allowing the prewarmed air to enter the building. In a north-western climate, the double façade it typically not a significant source of heat for a large building. For this reason, we are specifying Glass X, phase change material to contribute to the heating potential of the double façade. Glass X, has the heat storage capacity of 376 BTU’s a square foot. We have 100 square feet of this material at each floor at the spandrel and clerestory levels. Each floor has the heating storage capacity of 37,000 BTU’s. This material is comparable to a 9 inch thick concrete wall in regards to its heat storage capacity. In the winter, heat will flow out the operable spandrel windows at the bottom of each floor.
Figure 14: Test Bay Glare Analysis
d. Ventilation The double façade is to serve as a passive ventilation system that increases air
Figure 15: Ventilation
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e. Materials and Details Prototype Materials: - 2x6 Douglas Fir - Plexi-Glass (representing Eco-Resin) - Galvanized Steel Bolts and Nuts - Blue and Red Sharpie for Eco-Resin effect - Corrugated Plastic (representing phase change glass) - 1x2 Furring Strips BeesNist helped to analyze materials and evaluate environmental impact. Wood was the obvious choice however for longevity a wood/aluminum window system reduces exterior wear and environmental impact. Many of the materials intended for use for the dynamic shading system were too abstract to find on BeesNist however. Two major materials were the phase change glass and the eco-resin.
dynamic shading device is stationary it limited moving parts and made the design process straightforward. Dimensions were taken off the FIT Facility and for cost minimization and a performance standard the materials were acquired through Home Depot. Red and blue sharpies were used on the plexiglass as a means of replicating 3-Forms ecoresin material. The white corrugated plastic was a means of reducing lighting and simulating glass in its phase change state. Using University of Oregon’s Architecture woodshop the prototype was constructed with assistance from Tom Coats. Everything was hand constructed using a chop saw, jigsaw, tape measure and drill. (Figure 17)
Glass was originally intended to be used in place of the 3-Form product eco-resin however after analyzing its environmental impact and water consumption it was found to be a more harmful material and was substituted. Ecoresin is 40% recycled content and meets LEED certifications. The eco-resin also exceeds all VOC regulations for LEED certification. (Figure 16)
Figure 17: Exterior & Interior View of Dynamic Shading Device
RESULTS AND DISCUSSION Conclusion:
Figure 16: Glazing Embodied Energy
Prototype Construction: The process for the construction of the prototype was rather simple. Because the
Given the limited amount of data collected thus far from the FIT facility it is hard to make definitive claims about the success or failure of this dynamic shading device. However, it is clear the device itself is actively creating a different environment on the interior of the office bay.
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When analyzing the daylighting it appears to be working constructively as a shading device while still allowing most of the space to have adequate daylighting. Glare is reduced dramatically, in some cases the glare is reduced by over 50% in the viewing portion of the façade. The hardest glare to combat was the winter solstice, with the sun falling so low it was hard to keep glare out of the viewing window for interior occupants. While unable to model the double façade office accurately with phase changing glass among other things solar heat gain is reduced by 10%. This is an inaccurate percentage however modeled with correct materials would only increase the reduction of solar heat gains. The FIT Facility data taken over a two-week period at the times 9am, 12pm and 3pm indicated that the dynamic shading device is reducing sunlight between 19-33% during the month of December. A longer period of analysis would be beneficial to understand averages in depth. As well as data from the summer solstice and equinox. The solar heat gain cannot be measured accurately as the sensor is mounted on the outside and inside of a single pane glass window with a poor SHGC. The data is only reflecting the thermal properties of the window rather than the dynamic shading devices capabilities. If sensors had been set on the outside of the window and interior of the hallway, data may have been more conclusive. Limitation of the Study: The data from the FIT Facility is only 2 weeks long. To gain a true understanding of the performance of the shading device it would need to be analyzed over a greater period of time and with a larger budget to acquire more accurately representing materials.
The materials listed on BeesNist are limiting and for a better understanding of the environmental impact it would be crucial to gain a more developed idea of their sources, VOC, water and electricity consumption. ACKNOWLEDGEMENT: The authors would like to thank Professor Ihab Elzeyadi for his critiques and feedback throughout the research and design development. We would also like to thank Tom Coats for assistance and access to the University of Oregon’s woodshop. RESOURCES: Berge, Bjørn. The Ecology of Building Materials. 2nd ed. Oxford: Architectural, 2000. Print. DeKay, Mark; Brown, G. Z.. Sun, Wind, and Light: Architectural Design Strategies. Somerset: Wiley, 2013. Ebook Library. Web. 08 Dec. 2016. "Full Circle." 3form | Material Solutions. N.p., n.d. Web. 15 Nov. 2016. Greig, Anne L., Barbara C. Lippiatt, and Priya D. Lavappa. BEES 2.0: Building for Environmental and Economic Sustainability, Peer Review Report. Gaithersburg: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, Building and Fire Research Laboratory, 2010. Print. "High-Tech Glazing With Phase-Change Material." BuildingGreen. N.p., 2016. Web. 15 Nov. 2016. "Windows That Insulate like Walls." Heat Mirror Insulating Glass | Eastman Chemical Company. N.p., n.d. Web. 08 Dec. 2016.
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