Synergistic Effect of Paraffin-Incorporated In₂O₃/ZnO Multifold Smart Glazing Composite for the Self-Cleaning and Energy-Saving Built Environment

Abstract

The thermal performance of window glazing requires improvement for a sustainable built environment at an acceptable cost. The current work demonstrates a multifold smart composite consisting of an optimized In 2 O 3 /ZnO–polymethyl methacrylate–paraffin composite to reduce heat exchange through the combined self-cleaning and energy-saving envelope of the smart built environment. This work has attempted to develop a smart composite coating that combines photosensitive metal oxide and phase change materials and investigate their thermal comfort performance as a glazed window. It is observed that the In 2 O 3 /ZnO (5 wt %) multifold composite film experienced better transmittance and thermal performance compared to its other wt % composite samples. Moreover, the multifold composite-coated glass integrated into a prototype glazed window was further investigated for its thermal performance, where a steady average indoor temperature of ∼30 °C was achieved when the outside temperature reached ∼55 °C, while maintaining good visibility. Interestingly, the transparency reached ∼86% at 60 °C and exhibited a hydrophobic water contact angle (WCA) of ∼138°. In contrast, a similar film exhibits ∼64% transparency at 22 °C, where the WCA becomes moderately hydrophilic (∼68°). Temperature dependency on transparency and wettability properties was examined for up to 60 cycles, resulting in excellent indoor thermal comfort. In addition, a thermal simulation study was executed for the smart multifold glazing composite. Moreover, this study offers dynamic glazing development options for energy saving in the smart built environment.

An optimal climate-adaptable hydrogel-filled smart window for the energy-saving built environment

“…Two significant transmission properties of glazing called luminous transmission or reflection ( T lum ) and solar transmission ( T sol ) were acquired from eqn (1) and (2), 3,24 where T ( λ ) is the visible light spectral transmittance of the hydrogel filled glazing at a wavelength ( λ ), where 380 nm ≤ λ ≤ 780 nm, corresponding to human vision limits according to the CIE (International Commission on Illumination) standards. The solar irradiance spectrum for an air mass of 1.5 (AM1.5 ( λ )) was considered as the weighting function for the wavelength-dependent spectral transmittance.…”

“…Besides, measurements corresponding to 510 nm represent the CIE photopic luminous human eye efficiency. 24 Please do not adjust margins…”

“…The temperature profile of the hydrogel-filled prototype chamber was measured under 1000 W m À2 (1 sun 1.5 AM) of light from a Wacom AAA+ continuous solar simulator (model WXS-210S-20). 3,24 The solar irradiances also varied between 900 W m À2 and 800 W m À2 , corresponding to 0.9 and 0.8 sun conditions. The indoor and outdoor incessant temperature recording was performed with a TC-08 thermocouple data logger (Pico Technology).…”

“…Two significant transmission properties of glazing called luminous transmission or reflection (T lum ) and solar transmission (T sol ) were acquired from eqn (1) and (2), 3,24 T lum ¼…”

“…Besides, measurements corresponding to 510 nm represent the CIE photopic luminous human eye efficiency. 24 It should be noted that the transmission spectra results presented in this study are averaged values of ten repeated experiments. The high and low temperatures referred in this work are relative to the room temperature (22 1C) and relative humidity (B70%).…”