Abstract: Phase change energy storage composites were prepared using paraffin as the phase change material, High-density polyethylene ( PE-LD，high-density polyethylene (PE-HD)，polypropylene ( PP，and polystyrene(PS) as the supporting materials. }Che phase transition enthalpy of 68.44，45.52,40 .06，and 1 .19J/g were observed for PE-LD，PE-HD，PP, and PS matrixes, respectively. PE-LD was considered the best phase change matrix because of the highest phase transition enthalpy, which increased with increasing paraffin content. Diatomite and activated carbon could also improve the phase transition enthalpy and stability of phase change materials.

Key words: low-density polyethylene, paraffin, energy storage, phase change material