Multibelt freezers are mainly used for two purposes:
Applications with high production capacities and/or long residence times, which would otherwise require very long linear tunnels. By stacking multiple belts on top of each other, you can drastically reduce the overall dimensions of the freezer.
Applications where available space is limited. The compact design of the multi-belt freezer allows you to squeeze it in, where a single-belt freezing tunnel would not fit.
Due to its mechanical complexity, the specific thermal transfer efficiency per m² of belt is always less than that of a single belt freezer.