Heat transfer characteristic during crystallization of the phase change material (PCM) dispersed inside an emulsion is investigated theoretically and experimentally by using Differential Scanning Calorimeter (DSC) technique. The dispersed PCMs are hexadecane, octadecane and water. Nucleation laws are used to simulate the supercooling phenomenon. The results indicate that the crystallization of the droplets stabilizes the emulsion temperature at a value corresponding to that at which probability of crystallization J(T) increases rapidly. To describe with accuracy the thermal properties of the PCM using DSC technique it is more appropriate to represent these properties versus the sample temperature and not as function of the plate temperature of DSC.