Control of adiabatic properties using thermal meta-structures

In this study, the shapes and materials of thermal meta-structures, which can suppress as much heat propagation as possible in a structure, were investigated using a three-dimensional finite-difference time-domain technique. The heat flux vibrating in the traveling direction could be suppressed using multiple layers of thermal meta-materials. The heat flux transferred through the gap between thermal meta-structures could also be efficiently suppressed by placing even-numbered layers of thermal meta-structures in a zigzag arrangement in a structure. When the air-based thermal meta-structures were increased from one to four layers, the temperature inside the structure could be reduced from 38.9 °C to 25.5 °C. Moreover, when water-, paraffin-, aerogel-, and air-based thermal meta-structures having different thermal conductivities, densities, and specific heat characteristics were applied to the structure, a temperature of 50 °C to one side led to temperatures of 35.7, 33.4, 25.7, and 25.5 °C on the other. In other words, the temperature of the concrete block with air-based and aerogel thermal meta-structures was more than 13 °C lower than that of a conventional concrete block (38.9 °C), confirming that the insulation effect obtained by suppressing heat transfer was significant.