Quantification of Residential Energy Consumption Reduction Using Glass-Modified Asphalt Shingle

The urban heat island (UHI) phenomenon is defined as the differences in temperatures between urban and rural areas caused by the thermal properties of urban materials, urban geometry, and air pollution. Rooftops are playing a vital role in urban sustainability efforts and mitigating the UHI effect. Continuing these efforts, a study was conducted to evaluate the effectiveness of using recycled broken and waste glass cullet in the production of asphalt shingles to mitigate heat island effects and reduce building energy consumption by increasing the reflectivity of the roof asphalt shingles. To achieve this objective, shingle samples were prepared with and without glass cullet and the Solar Reflectance Index (SRI) of the specimens was measured based on ASTM E1980-11. The SRI of the asphalt shingles prepared with glass cullet and a white pigment powder was found to be 30, whereas it was 0 for the asphalt shingles without glass cullet. A three-dimensional transient finite-element (FE) model was formulated to investigate the thermal behaviors of glass-modified asphalt shingles as compared with convectional shingles. Measured SRI values were incorporated into the FE model, which simulated five climatic regions in the United States. Results showed that increasing the SRI of the roof would be beneficial, especially in hot climate regions where cooling load dominates most of the year.