Lightweight concrete façade with multiple air gaps for sustainable and energy-efficient buildings in Singapore

Building façades control the heat exchange rate between indoor and outdoor environment and, therefore, impact the operational energy for maintaining an ideal indoor temperature. In this study, a double skin concrete façade is proposed with multiple air gaps as thermal insulator. An ultra-thin façade skin is pursued by adopting textile reinforced ultra-high performance concrete (UHPC), while high thermal insulation is achieved by minimizing the convection- and radiation-related heat exchange across the air gaps. This new façade system is being compared to two commonly-adopted concrete façade systems: a solid concrete façade and a sandwiched concrete façade. A façade panel attached to a residential bedroom in Singapore is selected as the functional unit for assessing their carbon footprint, resulting operational energy, and costs. Results show that the new façade system has 34%–44% lower carbon footprint than the other two façade systems. The thermal conductivity of the new façade is 92% lower than the solid concrete façade and 64% lower than the sandwiched concrete façade, which helps reduce the related operational energy by 14%–49% for a typical bedroom unit in Singapore.