Structural characteristics and properties of CA-SA-PW/EG adsorbed into porous cement-based for thermal storage

Abstract

In this work, a ternary phase change material was manufactured by mixing capric acid-stearic acid (CA-SA) and paraffin (PW) and packaged and shaped with expanded graphite (EG) as a carrier. Four composite cement materials, PCM-1, PCM-2, PCM-3, and PCM-4, were prepared by direct mixing of CA-SA-PW/EG material cement mortar, and their thermal conductivity, thermal stability, and thermal storage properties were investigated. When the content of CA-SA-PW/EG reaches 15 % (PCM-4), the phase transition temperature of the composite phase change cement board is 28.06 ℃, the latent heat of phase change is 0.56 J/g, and the thermal conductivity is 1.566 W/(m-K). In the 400 W light experiment, the PCM-4 temperature damping reached 1.30, and the surface temperature inside the PCM-4 miniature experimental room was warmed up from 22 ℃ to 32 ℃ consuming 2780 s, so that the appearance of the peak temperature was effectively delayed. With the gradual increase of phase change material content, the delay phenomenon is more obvious, and the maximum temperature difference between the inner and outer surfaces of PCM-4 is 14.039 ℃, which is 62.5 % larger than that of ordinary cement board. Expanded graphite-based composite phase change cement materials can effectively improve thermal comfort and reduce energy consumption in buildings.