Compressive strength, thermal reflectivity and energy saving of nano-TiO2-based inorganic decorative panels

The utilization of thermal reflective materials on the building surface is one of the most promising methods for energy-saving in tropical and subtropical regions. In this work, nano TiO 2 (NT) is used to enhance the mechanical properties and thermal reflectance of inorganic decorative panels, which are widely used for building exterior walls in China. The obtained results show that NT can modify the pore size distribution of the decorative panels and reduce the presence of macropores, and the compressive strength of the decorative panels with 2% NT increased by 4.78%. The thermal reflective properties of the decorative panels initially increased and then decreased with increasing NT content and particle size. Notably, the panels made of 6% NT with a particle size of 100 nm exhibited higher thermal reflectivity, resulting in a surface temperature decrease of 3.9 °C compared to the reference sample. Furthermore, compounding different particle sizes NT is employed to produce the decorative panels, and about a 4.5 °C decrease can be observed in this study. Mid- and far-infrared absorption spectroscopy results show that the thermal emissivity is improved in the mid- and far-infrared region of 2.5–25 μm when 100-nm and 25-nm NT were compounded at a weight ratio of 1:1. Additionally, to further evaluate the energy-saving of the decorative panels, the Designer’s Simulation Toolkit (DeST) is employed, which demonstrates that the thermal reflective decorative panels with 6% NT can save 7.19% of building air-conditioning energy consumption and reduce the indoor temperature by 1.5 °C.