In this study, ten kinds of composite phase change materials (PCMs) were prepared by impregnation of xylitol penta palmitate (XPP) and xylitol penta stearate (XPS) esters into gypsum, cement, diatomite, perlite and vermiculite via vacuum adsorption method. The form-stable composite PCMs were characterized by using SEM and FT-IR, DSC and TG analysis techniques. The maximum impregnation ratio of both XPP and XPS into gypsum, cement, perlite, diatomite, and vermiculite were found to be 22, 17, 67,48 and 42 wt%, respectively. The DSC results showed that the melting temperatures and latent heat capacities of the composite PCMs varied from 20 degrees C to 35 degrees C and from 38 J/g to 126 J/g. TG investigations revealed that the composite PCMs had excellent thermal durability above their working temperature ranges. The thermal cycling test also exhibited that the composite PCMs had good thermal reliability and chemical stability. In addition, thermal conductivities of the composite PCMs were increased by addition of EG in mass fraction of 10%. All of the conclusions indicated that among the prepared composite PCMs, especially perlite and diatomite based-PCMs are potential candidates for energy storage applications such as solar heating and cooling in buildings since they had relatively higher latent heat capacity. (C) 2012 Elsevier B.V. All rights reserved.