Performance of Smart Glazed Overhang Systems for US Residential Buildings

In this chapter, the application of smart glazing systems as shading devices is evaluated for US residential buildings. Specifically, static and dynamic overhangs are considered using smart glazing that can change their tint state to reduce the heating and cooling thermal loads for prototypical housing units in high-rise apartment buildings. The tint settings as well as the overhang tilt angles are specified on hourly, daily, and monthly basis depending on the window orientation and the time of the year to minimize the annual energy demand for the housing unit. The performance of smart glazed overhang systems is compared to both static and dynamic shading devices made-up of conventional opaque materials. In addition, the impacts of various design and climatic conditions are considered to assess the energy performance of the smart overhangs. The results of the analysis indicate that the annual energy consumption for a typical housing unit located in Boulder, CO, can be reduced by over 7% for static smart overhangs and over 22% for dynamic smart overhangs for a typical housing unit located in Boulder, CO. These savings are even higher with larger windows and wider differentials between optical properties between clear and dark states. Smart overhangs allow the use of low-cost smart glazing for existing and new constructions as well as allow specification of large windows with limited energy penalties.