Thermal Conductivity of Lightweight Solid Bricks Made From Waste Mixtures and Its Impact on Building Energy Efficiency

This study investigates the thermal conductivity of lightweight solid bricks made from waste mixtures and evaluates their impact on building energy efficiency. The waste materials used in the brick mixtures include plastic, paper, rice husks, wood shavings, and coconut fibers, with cement and sand as primary components. Seven variations of these mixtures were analyzed, and thermal conductivity measurements were conducted using a Quick Thermal Conductivity Meter, supplemented by theoretical calculations based on the general heat transfer equation. The study also applied the Overall Thermal Transfer Value (OTTV) method to assess the bricks' contribution to energy efficiency, incorporating them into cube-shaped and office building models. The results reveal that the thermal conductivity of the bricks ranges from 0.48 to 0.82 W/m°C, with porosity values between 12% and 26%. Compared to conventional bricks, those incorporating waste materials demonstrate a modest improvement in energy efficiency, reducing the OTTV by 5% to 13% in cube-shaped models and by 0.2% to 0.69% in office buildings. These findings suggest that while the bricks made from waste mixtures provide some benefits in terms of energy efficiency, further optimization of the material composition is necessary to achieve more substantial improvements.