Evaluating effective thermal conductivity of PCM-impregnated wood composite at phase change temperature

Abstract

This study examines the effective thermal conductivity of wood composite impregnated with phase change material (PCM) during the PCM phase change process. Incorporating PCMs into wood stabilizes its shape and boosts energy storage capacity, broadening its applications in buildings while reducing energy usage. Most previous studies on PCM focused solely on acquiring the thermal conductivity in their solid state, leaving a gap in research concerning their liquid state. In this study, a PCM-impregnated wood composite was developed with bio-based binders. The effective thermal conductivity was analysed across a temperature spectrum in which the impregnated PCM, ethyl palmitate, exists in three distinct phases: solid, liquid, and mushy (a mix of solid and liquid phases). The results indicate a notable variation in effective thermal conductivity during the phase change process. At 10 °C, the solid PCM has an effective thermal conductivity of 0.13 W/m·K, while at 40 °C, its liquid state maintains the same value. However, a significant 48 % increase in effective thermal conductivity was observed during the phase change temperature measured using a hot disk instrument. These findings are expected to provide valuable insights for both researchers and industrial sectors that use PCMs for TES.