The distribution of ice-rich layer in an ice storage tank is an important factor to estimate the thermal performance of a dynamic-type ice storage system. The ice-rich layer distribution and the water permeability were tested by using cylindrical tanks. The accumulation of ice-rich layer was predicted by a model analysis in which Darcy's law was applied. From the results of both experiments and analyses, the effect of water flow rate on the time history of the ice-rich layer formation were revealed. An average downward superficial velocity in the ice-rich layer is a dominant factor in the component design for an efficient use of an ice storage tank. This calculation model for the distribution of ice-rich layer can be considered to be applicable to realize the high thermal performance for large-scaled ice storage tanks.