Abstract: Numerical results pertaining to cyclic melting and freezing of an encapsulated phase change material (PCM) have been reported.The cyclic nature of the present problem is relevant to latent heat thermal energy storage system used to power solar Brayton engines in space.Specially,a physical and numerical model of the single tube phase change heat storage system was developed.A high temperature eutectic mixture of LiF CaF 2 was used as the PCM and dry air was used as the working fluid.Numerical results are compared with available experimental data.The trends were in close agreement.