Thermal conductivity enhanced polyethylene glycol/expanded perlite shape-stabilized composite phase change materials with Cu powder for thermal energy storage

Phase change materials (PCMs) have been widely investigated for thermal energy storage due to their excellent heat storage densities and narrow operating temperature. However, their poor thermal conductivity and shape stability during utilization always restrict their further application. In this paper, polyethylene glycol/expanded perlite phase change materials with Cu powder phase-change materials (PEG-Cu/EP PCMs) are prepared by vacuum impregnation to overcome these problems. The results indicated that Cu particles are well dispersed in PEG and uniformly enwrapped inside the pores and surfaces of EP due to their excellent physical interactions by capillary force and surface tension. Thus the as-prepared composites exhibit superior shape stability around the working temperature around 253 °C. Furthermore, when 9.35% Cu powders are added into PEG, its thermal conductivity of corresponding composite is significantly enhanced by 129.9%, with a nearly invariable phase change enthalpy at the same time. Therefore, the PEG-Cu/EP PCMs are confirmed to be promising energy storage materials for applications in solar energy generation, building energy conservation, and industrial waste heat utilization.