Thermal conductivity of high-temperature multicomponent materials with phase change

This work focuses on the investigation of the effective thermal conductivity (lambda(eff)) of heterogeneous materials consisting of a phase change material (PCM) and expanded graphite (EG). These composites may be employed in latent heat storage systems, where a PCM stores energy by being heated to a temperature higher than its melting point (T-m), and releases it during solidification. For the determination of lambda(eff), the steady-state comparative method was used and modified to measure composite samples at temperatures above T-m. Results were compared with the thermal conductivity of the pure PCMs, and a significant increase could be observed. The dependence of lambda(eff) on temperature, as well as the influence of the material microstructure on the enhancement of lambda(eff), were examined.