Thermally conductive and form-stable phase change composite for building thermal management

Abstract

Phase change materials (PCMs) have aroused tremendous interest in building thermal management (BTM) owing to their operational simplicity and comparable energy storage density. However, the application of PCM-based BTM is generally hindered by the bottlenecks of low thermal conductivity and liquid leakage. To solve this problem, a novel thermally conductive and form-stable phase change composite (PCC) is prepared by employing n-Octadecane (ODE) as PCM, olefin block copolymer (OBC) as supporting material, and expanded graphite (EG) as thermally conductive additives. The characterization results show that the as-synthesized PCCs exhibit good physicochemical compatibility. The introduction of EG enables PCC an enhanced and antistrophic thermal conductivity. The radial thermal conductivities of PCCs reach up to 3.8–20.6 W/m∙K with EG loading of 5–25 wt%. The thermogravimetric analyzer (TGA) and leakage-proof analysis indicate that the resultant PCCs have a good thermal stability and the combination of OBC and EG greatly alleviated the leakage problem. In addition, BTM test shows that the indoor temperature of the PCM room is more stable and the maximum temperature differences between PCM room and reference room are 2.5 °C and 3.6 °C during the heating and cooling processes. These results indicate that the as-synthesized ODE-OBC/EG composites have significant potential for BTM application.