Three kinds of porous matrix-Na2HPO4·12H2O composite materials were prepared by the molten phase change material Na2HPO4·12H2O which was infiltrated into the porous material carbon sponge

foam nickel

foam copper. Composite phase change materials were melted at 55 ℃ in a constant temperature water bath

and then cooled at 20 ℃ in room air. A number of cycle tests were conducted. Temperature data logger acquisition was used to collect temperature change data of composite phase change materials when the phase change materials were melted and cooled. Then

phase change material melting temperature and phase transition undercooking were measured

using scanning electron microscopy to observe the structure and morphology of composite phase change materials.The experimental results show that though a porous material has almost no effect on the melting temperature of the phase change material

it can reduce the undercooking of Na2HPO4·12H2O and shorten the melting start of the phase change material and the melting process.