This paper mainly deals with a novel homogeneous phase change process in materials (HPCP). The HPCP is analysed in detail and the expressions for one-dimensional HPCPs are derived. It is concluded that, compared with the conventional phase change processes, the complete phase change time of HPCPs can be decreased by 60% for a spherical phase change material (PCM), 50% for a cylindrical PCM and 33% for a flat plate PCM, respectively, and the application of HPCPs to thermal energy storage systems can charge or discharge thermal energy with constant rates. Possible applications of HPCPs to thermal energy storage are simulated and further discussed using composite flat plate PCMs.