Thermal performance of sculptured tiles for building envelopes

Since effective thermal insulation of buildings could significantly decrease energy consumption worldwide, this study examined the potential of concrete tiles with complex geometries at improving thermal performance in building envelopes. The study focused on air flow characteristics that occur near the external surface of the tile, and their influence on the rate of heat transfer within the material. Six groups of sculptured tiles were developed, using a systematic approach (i.e., repetition of basic geometries), biomimicry, and inspiration from natural envelopes. Air flow behavior and heat transfer rates were examined at three different wind speeds, through both experiments and computational fluid dynamics simulations using a configuration of flow impingement that can be regarded as the worst case scenario. After successfully validating the data, additional numerical simulations were conducted for all developed tiles using the Star-CCM + commercial software. The results showed an improvement in the insulation performance of about half of all the tested cases. Moreover, significant improvements were seen in the geometries that mimicked animal fur, achieving heat transfer rates that were up to 24% lower than those achieved by smooth tiles. Our results indicate that the application of such tiles with increased thermal resistance could save on thermal insulation materials and improve the thermal performance of building façades.