Fabrication and characterization of docosane–dodecanol composite phase change materials for low-temperature domain thermal energy storage and recovery

Abstract The docosane–dodecanol (DE-CP) binary phase change materials (PCMs) were prepared to improve the heat diffusion performance of the photovoltaic/thermal (PV/T) system in this work. The phase transition temperature of DE-CP matches photovoltaic heat dissipation requirements, with 60 wt% DE achieving optimal latent heat of 243.8 kJ/kg. Expandable graphite maximizes expansion at 900°C for 60 seconds, resulting in high pore volume and adsorption capacity. Incorporating expanded graphite into DE-CP increases thermal conductivity from 0.135 to 1.383 W/(m·K) and ensures excellent compatibility and cyclic stability. This paper provides a reference for further development and integration of composite PCMs in solar PV/T systems.