June 04, 2020
Creating an Energy-Efficient Façade for the Hot Desert Climate
by Guest Blogger
The city of Doha, Qatar, is known for its futuristic architecture that pushes the boundaries of modern building techniques. The climate is also one of the world’s most demanding, with temperatures regularly stretching well above 100 F. Here’s how performance and striking design came together at the recently completed Qatar National Library, with Super Spacer® TriSeal™ Flex from Quanex.
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Housing more than one million books, 500,000 digital editions, and a variety of irreplaceable scriptures and manuscripts on Arab-Islamic civilization, the Qatar National Library was designed to highlight the cultural importance of its collections while offering visitors a pleasant and comfortable environment in which to enjoy them. The exterior’s striking 5,500-square-meter glass façade welcomes guests, creating a unique look in the cityscape.
In this kind of architecturally ambitious structure, energy efficiency must be considered in every design choice. Doha’s climate requires high performance, especially in glass elements. To achieve the necessary performance in the building’s façade, architect Rem Koolhaas and glass manufacturer CRICURSA Cristales Curvados used Super Spacer® TriSeal™ Flex and some innovative glass design techniques.
"Qatar is one of the region’s most markedly affected by the rise in average temperatures caused by climate change,” explains CRICURSA’s marketing director Joan Tarrús. "Outdoors, where temperatures exceed 100 degrees Fahrenheit in the summer, the temperature inside the library should be a pleasant 68 degrees. The energy-related and thus production-related challenges placed upon the façade glazing were enormous, especially in view of the fact we did not want to plan for mechanical shading under any circumstances.”
Super Spacer TriSeal Flex, designed specifically for curved glazing, was ideally suited for the challenge, providing excellent thermal performance and structural stability for the unique corrugated glass design of the façade chosen by the architect. In a manner resembling the corners of a box being folded up, the glass façades form the shape of a diamond. They filter out the glaring sunlight and illuminate the library with as much diffuse, glare-free daylight as possible. The light is reflected down into the room via a white aluminum ceiling. The absence of metallic elements in the glass façade eliminates potential thermal bridges that conduct heat into the interior of the building, which could weaken the insulating effect of the gas layer and warm edge in the curved double glazing.
"In this climate region, the use of a warm edge for double glazing is indispensable in order to optimize the energy efficiency of a building," said Joachim Stoss, managing director of Edgetech Europe GmbH and vice president, International Sales at Quanex. The constant transition between hot sunlight, shade and cooler night temperatures leads to the permanent movement of the glass, and consequently, to considerable mechanical stress on the edge seal. "Flexible spacers such as Super Spacer hermetically seal the space between the panes for many years. Due to the properties of the structural foam, the spacer system absorbs the pumping motions of the panes and prevents wear of the primary seal.”
The arrangement of the curved glazing also ensures the façade is self-supporting and exceptionally resistant to wind loads. Compared to a flat glass surface with an identical pane thickness, the corrugated shape enables much higher loads to be transferred. In Doha, the steel bases between the glass elements were connected with interior columns to provide the construction with even more stability.
The project is a true example of how Super Spacer TriSeal can help dramatic commercial glass designs achieve the necessary thermal performance in the world’s most challenging climates. Read more Quanex case studies in our archive.
June 04, 2020 by Guest Blogger