Novel Thermal Break Solution
Thermal-break-blanket technology contributes to high performance and design freedom
Presented on October 12, 2022 at Facade Tectonics 2022 World Congress
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Overview
Abstract
Thermal-break-blanket technology is a novel and high-performance thermal break solution for aluminum curtain walls. The thermal-break-blanket is installed between the metal frames to reduce heat loss like traditional thermal break materials. However, the thermal conductivity of the thermal-break-blanket is 0.011 Btu/h∙ft∙°F (0.019 W/m∙K), which is between 6 to 15 times lower than traditional thermal break materials. In addition, the thinness and pliability of thermal-break-blankets allow for the achievement of both high-performance and versatility in design.
This paper presents a case study for the Guoxin Haitian Center T2 Tower, the tallest building in Qingdao, China, which adopted the thermal-break-blanket technology as the primary thermal-break type for its curtain wall system. The team used THERM and WINDOW software to evaluate thermal performance simulations during its design phase. By comparing six curtain wall systems that combine two glass types and three frame types, the thermal-break-blanket technology demonstrated significant advantages in terms of high thermal performance, cost-effectiveness, and design freedom. Results showed that compared to the benchmark, the application of thermal-break-blanket indicated significantly reduced thermal transmittance of the curtain wall system where the overall U-factor was lower by 37%, and the interior surface temperature was higher by 46°F (8°C). Actual Performance Mock-up testing was also conducted prior to construction. Those results indicated a similar overall U-factor of 0.30 Btu/h∙ft2∙°F (1.7 W/m2∙K) and confirmed the simulation predictions.
Authors
Yuzhen Steve Zhou
Technical Director - Warmframe Technology Corporation
s.zhou@warmframe.com
Keywords
1. Introduction and Background
Design freedom, high thermal performance, and cost-efficiency have never been more urgently needed as nowadays since most countries have joined the Paris Agreement and made their own clear and solid commitments. The Chinese government has also committed to reaching the carbon peak by 2030 and carbon neutral by 2060 [1]. Energy codes and public policy are the primary drivers for facade innovations [2]. Thus, developers, architects, and contractors have been actively seeking innovative and better energy-efficient solutions.
The Guoxin Haitian Center is a mixed-use complex in Qingdao City, China (Fig. 1). The project includes three high-rise buildings, and the total gross floor area is 5,274,500 ft2 (490,000 m2). The 369-meter tall T2 Tower within the multiple-building complex is the tallest building in Shandong province as of 2021. The architectural design was inspired by "Rhythm of the Sea". The building facades are like waves in the sky, layer by layer rotating by height, all the way from the bottom to the top of the building.
The T2 Tower is characterized by about 10,000 irregularly placed unitized curtain wall panels to realize the natural pattern of undulating waves. None of the adjacent panels are in the same plane horizontally and vertically (Fig. 2).
Not only are all the unitized curtain wall panels jagged, but the inward and outward projection distances vary panel by panel as well. The maximum in-and-out length is 1.75 feet (53.1 cm), which happens at the corners where the curvature changes. As a result of such aesthetically-driven customization, the design team was additionally challenged in resolving performance issues regarding air and moisture tightness and structural safety of the facade systems. (Fig. 3).
2. Research Questions and Methods
As is common on many fast-paced, large-scale projects, the design team was faced with additional challenges to drastically improve building performance beyond minimal local codes late into the project schedule
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3. Analysis of Results
3.1. Therm Simulations
Due to strong preferences for a very slim aluminum profile from an aesthetic perspective, the visible width of the aluminum frame projection is relatively small and barely
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4. Conclusion
Through this case study, we demonstrated the usage of the thermal-break-blanket technology in the curtain wall of the Guoxin Haitian Center T2 Tower. The thermal-break-blanket's superior thermal conductivity and flexibility
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Acknowledgements
The author would like to acknowledge the project team for their support:
Developer – Qingdao Guoxin Group
Facade consultant - Meinhardt Facade Technology
Facade contractor – Jangho Group
The author would like to acknowledge Mr. Abel Yang of Meinhardt Facade Technology for providing valuable information and comments.
Rights and Permissions
[1] UN News. 2021, China headed towards carbon neutrality by 2060, United Nations
https://news.un.org/en/story/2021/09/1100642
[2] Sanders H. 2021, Is More Façade Innovation What We Need? Part 2, USGlass Magazine
https://www.usglassmag.com/insights/2021/05/is-more-facade-innovation-what-we-need-part-2/
[3] NFRC. NFRC 101-2020_E0A5 Procedure for Determining Thermophysical Properties of Materials For Use in NFRC-Approved Software. National Fenestration Rating Council, Inc.
[4] China National Standard. GB/T 8484-2008 Graduation and test method for thermal insulating properties of doors and windows. China National Standardization Administration.
[5] NFRC. 2021, THERM 7 / WINDOW 7 NFRC Simulation Manual. National Fenestration Rating Council, Inc.