CAREER: Understanding the Thermal and Optical Behaviors of the Near Infrared (NIR)-Selective Dynamic Glazing Structures

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The objective of this Faculty Early Career Development (CAREER) Program award is to understand the thermal and optical behaviors of windows consisting of multi-layer functions and near infrared (NIR)-selective effects. An ideal window should seasonally respond to the solar heat, while transmitting the visible light. However, current window technologies are challenged to modulate solar heat independent of visible light. Recent advances in nanomaterials have demonstrated the ability to independently manipulate NIR light. This project will integrate the nanoscale physical relations and effects of nanomaterials on the thermal and optical behaviors of multi-layer glazing structures. The societal impacts of the project will constitute a new class of building windows that can greatly reduce the total building energy consumption in the nation. The educational impacts will include courses concentrating on building windows and envelopes, which bridge the knowledge and ignite collaborative interest between the architecture and engineering communities for cultivating future professionals in the sustainable building industry. Furthermore, experimental modules will be created to teach high school students to build their own sensors for window measurements and to raise community and public awareness of energy-efficient window technology.To achieve the objective, the research approach includes: (1) decomposing global solar irradiance into its spectral band components to achieve a time-dependent NIR model; (2) deriving and experimentally validating the fundamental thermal and optical behaviors of NIR-selective glazing structures; and (3) integrating the thermo-optical model and NIR model for the evaluation and optimization of dynamic NIR-selective glazing structures. This research will form the foundation to understand the combined effects of nanoscale phenomenon (i.e., photoexcitation) and micro-to-macroscale glazing structure properties (i.e., glazing properties, spectral emissivity, central-layer insulating abilities, layer placements). Such knowledge will significantly improve our ability to incorporate NIR-selective materials into building windows. New analytical models that take the nanoscale NIR absorption and scattering features into account will be developed and experimentally validated. By coupling the developed solar spectral decomposition model and computational method to quantify glazing performance, this research will provide an understanding of the salient characteristics and patterns of the optimal time-dependent thermo-optical properties of NIR-selective glazing structures to achieve a minimum level of energy use.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.