Abstract A pore-scale numerical model is presented for simulating the melting of phase change material (PCM) in a PCM-metal foam composite energy storage system. Instead of considering volume averaged domain for simulating the melting process, the present model resolves the geometry of the metal foam. Thus it can capture the effects of geometrical parameters such as the pore size and pore distribution as well as the localized heat transfer at the metal foam PCM interface more accurately. The model also incorporates the effect of convection on the melting process. The developed model comprises of a geometry creation model for generating the foam structure considering metal foam as overlapping circular pores of different pore radius. Heat transfer, phase change and convection are solved using an enthalpy based finite volume model. The model is validated with experimental results given in literature. Subsequently, the effect of convection on melting and energy storage rate in PCM-metal foam composite systems is studied for different pore size and different porosity of metal foam. Results indicate that the effect of convection is higher for higher porosity and larger pore size.