Building glass retrofitting strategies in hot and dry climates: Cost savings on cooling, diurnal lighting, color rendering, and payback timeframes

Abstract

Building glazing is a weak thermal envelope that admits too much solar heat, resulting in increased air conditioning expenditures. An optimal glazing system must be chosen to promote the thermal and visual comfort of building interiors. The current study examines how different glass retrofits affect the air-conditioning cost savings of an office building in a hot and dry region of India. To assess the thermal performance of the building, the apertures of the office building were retrofitted with brick glass, stained, tinted, reflective, laminated, polymer dispersed liquid crystal film glazing, and double-glazed window systems. The spectral characteristics of the studied retrofit glazing systems were measured experimentally, and a mathematical model was developed to estimate the heat gain, cooling cost demand, and energy savings for air-conditioning. The polymer dispersed liquid crystal film glazing retrofit provided the highest average air-conditioning cost savings (5.11 $/m2), while the air-filled double-glazing configuration showed the lowest (0.30 $/m2), relative to the original glazing installation among the other retrofits tested. The examined retrofit glazing systems have a colour rendering index of more than 80, indicating appropriate lighting quality. The findings of this study are critical in determining the most energy-efficient retrofit glazing solutions for energy-conscious building design.