Design of thermo-chromic glazing windows considering energy consumption and visual comfort for cellular offices

Abstract

Optical behavior of thermo-chromic glazings can be modulated with changing temperature based on phase transmission of embedded pigments. Such pigmented glazings can be used in residential or office windows to alter visible and solar transmittance of the window, based on environmental conditions. This study focuses on numerical design of thermo-chromic glazings with V O2 pigments used in office buildings so that energy consumption can be minimized, while considering visual comfort. Optical properties of pigmented glazing depends on pigment radius, volume fraction and glazing thickness. In this study, two main design variables that are pigment radius and volume fraction are examined by applying parametric analysis for a constant glazing thickness that is identical to a standard ordinary glass. The radiative transfer through glazings are solved using four flux method to predict the optical properties of the glazings. The optimum thermo-chromic glazings are identified and energy efficiency along with resulting daylight illuminance are compared with that of an ordinary double glazing for several geographical locations. It is observed that thermo-chromic windows for office buildings have significant energy saving potential which can lead decreases in energy consumption from 17% for cold climates to 42% for hot climates.