Crystal mud transparent slime as a glazing material for net-zero energy buildings: Enhanced energy savings, diurnal lighting, and CO2 mitigation

Abstract

Modern buildings are highly glazed and necessitate an enormous amount of energy to maintain thermal and visual comfort. To reduce the energy requirements of such buildings, conventional glazings should be replaced by energy-efficient glazing systems. In this paper, the cost-effective insulating material is used in the glazing application. This glazing system is made by filling the crystal mud transparent slime (TS) in the air gap of the conventional double-glazing unit. The solar-optical and colour rendering properties, thermal properties, solar heat gains, yearly net operating costs and cost savings, repayment period, and CO2 emission mitigation of transparent slime glazings with varied gaps, including 4 mm, 8 mm, and 12 mm, were evaluated. These evaluations were made for the Sholapur (hot and dry) and Lucknow (composite) climatic zones of India. This study revealed the potential of TS glazings in reducing the heat gains, net operating costs and CO2 emissions compared to conventional double-glazing units (ADGUs) with 4 mm, 8 mm and 12 mm air gaps. In comparison to conventional air-filled double glazing with a 12 mm gap (ADGU-12), transparent slime glazing with a 12 mm gap (TS-12) has demonstrated the greatest savings in heat gain of 21.3 % and yearly net operating cost of 21.32 %. TS-12 has recorded the highest cost savings of $132.62 and $119.85 for the Sholapur and Lucknow climatic zones respectively. TS-12 obtained the highest CO2 emission mitigation of 2.107 (tCO2/year) for Sholapur climatic conditions. All the TS glazings have shown a very less repayment period ranging from 4.97 to 6.16 years. Daylighting analysis for a dining hall building model with TS glazings revealed adequate natural illumination inside the building. All the TS glazings have shown good colour quality and uniform daylighting. This work gives a novel idea for reducing the energy consumption of buildings.