Development of smart glazing techniques for efficient buildings

In recent times, the buildings sector has emerged as a major consumer of energy in urban areas. Among various contributors, windows in the external envelope of buildings are particularly responsible for a significant portion of energy consumption due to their high thermal conductivity. The integration of smart films with traditional glazing has been explored as a means to modify the opt properties of windows. However, this integration can affect the visual connection between occupants and the outside views. This thesis focuses on advancing smart windows to enhance their thermal and daylight performance, with two main developments proposed. The first development involves the use of double-glazed ventilated windows in cold climate regions. These windows utilise waste air from the building for ventilation. However, existing research indicates that under certain conditions, the waste air may be insufficient to maintain proper ventilation. To address this, the thesis proposes validated procedures that optimise the utilisation of waste air, enabling sustained ventilation for longer periods. This optimisation contributes to improved thermal efficiency of ventilated windows and energy savings in buildings. Experimental results obtained from a small-scale test room demonstrate that implementing the proposed optimisation process can achieve energy savings of up to 83% compared to conventional double-glazed windows. The second development focuses on integrating a double-glazed window with a polymer dispersed liquid crystal (PDLC) film for hot climate regions. Previous research overlooked the impact of reduced optical transmission on the window's visual clarity. This thesis introduces an image-processing quantification algorithm for evaluating the visual experience through PDLC windows. The algorithm identifies the comfortable visible range and determines the lowest acceptable transparency level to maintain satisfactory visual communication with the outdoor environment. Experimental results from a small-scale test room indicate that implementing the proposed quantification process enables the provision of a customized range of visual quality based on user preferences. The system also ensures that the operating visibility does not fall below a pre-defined threshold level. The trial illustrates that altering the PVR ratio from 0 to 1 has the potential to alter the mean contrast value in a clear sky setting, shifting it from 0.18 to 0.37. Additionally, in order to ensure a minimum acceptable vision quality, the proposed algorithm ensures that the optical transmittance of the window remains above a specified threshold value (