This paper describes a numerical model to predict the dynamic performance of an internal melt ice-on-coil storage tank during full as well as partial charging and discharging cycles. Partial charging and discharging cycles may occur when the peak load is not high or when the charging/discharging time is limited, especially under real-time pricing rates. The model presented in this paper takes into account the mass effect of each layer of ice and water. The model predictions are validated using experimental data obtained from tests conducted under laboratory controlled conditions for both partial charging and discharging cycles. Moreover, parametric analyses are carried out to evaluate the effect of various operating conditions on the thermal performance of the internal melt ice-on-coil storage system and the energy efficiency of the chiller under partial charging and discharging cycles.Units: I-P