Crushed Rubber from Used Tires for Thermal Insulation of Walls and Flat Roofs: Modeling, Validation and Comparison with Conventional Technology

摘要

Heating and cooling of buildings is responsible for almost 40% of the electricity demand and about 33% of greenhouse gasemissions. Because of the global energy and environment critical situation, there is a need to improve the energy efficiencyof buildings and make them more sustainable. The main objective of the present study is to investigate the crushed rubberfrom unserviceable tires as an insulating material for walls and flat roofs and to provide an additional route for their reuseand deviation from landfills. An experimental rig is constructed and instrumented to determine the thermal conductivity ofcrushed rubber from used tires and the overall thermal conductivity of composite walls and roofs with crushed rubber insertion.Experimental measurements showed a thermal conductivity of crushed rubber of about 0.25 W/m. A conduction modelis formulated for multilayered plane wall, discretized in explicit form and used to elaborate a home built code in MATLAB.The numerical code was tested and validated. Numerical investigation was done to analyze the effects of the wall thickness,thermal conductivity of the material, color, gap dimension and rubber filling on decrement factor, the time lag and totalinternal heat gain. The simulations indicated 21% reduction in the decrement factor and an increase of about 1.63 times inthe lag in comparison with the plastered wall. The flat roof showed 23.3% reduction in solar heat gain, by increasing therubber layer thickness from 15 to 25 cm.