Numerical evaluation of thermal performance and improvement strategies for 3D printed concrete structures

The building and construction sectors are major contributors to the world's energy consumption, which necessitates new innovations such as construction 3D printing technology where concrete can be deposited precisely to tune the thermal performance. With this backdrop, this study aims to investigate the thermal transmittance of four lattice structures, namely honeycomb lattice, single triangular lattice, double triangular lattice, and square lattice, which have been previously studied for their mechanical performance. Through numerical simulations, the intricacies of heat transfer mechanisms within the complex cavities have been discussed with the role of different heat transfer modes. The numerical results reveal that, while square lattice exhibited the lowest thermal transmittance (4.39 W/m2K), it exceeds regulatory requirements by a considerable margin (9 times higher). To address this disparity, the study explores two physics-driven approaches: cavity insulation and the application of plastering to both internal and external structures. These strategies exhibit promising results, yielding substantial reductions in the U value by 102% and 290% respectively. The scientific study revealed that despite having low thermal conductivity (of insulation material), cavity insulation could not significantly reduce the U value compared to plastering owing to the nature of the arrangement of thermal re-sistances. However, from an economic standpoint, insulation cost was found to be almost 15 times lower than that of plastering. This investigation provides novel pathways to tackle the thermal challenges of 3D-printed lattice structures and prompts the research community to delve deeper into the domain for a com-fortable built environment at an economical cost.