Neopentyl glycol (NPG) was saturated into the compressed expanded natural graphite (CENG) matrices with different densities in an attempt to increase the thermal performance of NPG for latent heat thermal energy storage (LHTES) application. NPG uniformly disperses in the porous network of the expanded graphite. Measured results indicated that thermal conductivities of the composites can be enhanced 11 -88 times as compared with that of the pure NPG. The latent heat of the NPG/CENG composites increased with the increasing mass ratio of the NPG in the composites. Compared with the pure NPG, the deformation of the composites due to phase change has been greatly reduced. After phase transition, thermal conductivity of the composites decreased slightly. The trends concluded from the finite element simulation are coincident with the trends from the thermal imager. (C) 2012 Elsevier Ltd. All rights reserved.