The synthesis, thermal energy storage properties and thermal reliability of some fatty acid esters with glycerol as novel solid-liquid phase change energy storage materials were investigated. The esters were synthesized by means of the Fischer esterification reaction of the glycerol with myristic, palmitic and stearic acids. The chemical structures of esters were proven by FT-IR and (1)H NMR techniques. The melting temperatures and latent heats of the synthesized esters were found in the range of 31-63 degrees C and 149-185 J/g, by DSC method. The results showed that the esters as phase change materials (PCMs) had good thermal reliability with respect to the 1000 thermal cycles. TGA analysis was performed to determine thermal stability of the esters. The thermal conductivity of the PCMs was also improved significantly by adding 5 wt% expanded graphite. Based on all results it can also be concluded that the synthesized esters can be considered as potential PCMs for thermal energy storage. (C) 2010 Elsevier B.V. All rights reserved.