Storage of ice slurries is advantageous to save energy and to produce a continuous controlled long-time operation of an ice-slurry system. To guarantee homogeneous ice particle fields and to prevent a system of blocking by ice clusters, up-to-present a good mixing of the slurries was proposed. But mixing can lead to twenty percent energy demand of the total energy con-sumption of an ice slurry system, including the production of cold. Therefore, new methods are invented to operate systems without a mixing in the storage tank, but still with a control of the fluid and flow conditions in the piping circuits. The theoretical basis to calculate distributions of ice particle fields, respectively ice concentration distributions in unmixed ice slurry storage tanks with stratifications is given and first numerical simulation results are presented.