The set count follows from the dispatch interval and the time a set takes to become ready again; how many plates fit in one box has no part in this sum. In GEBHARDT's table the recommended freezing time is 24 hours for every eutectic plate (for a plate with a -21 °C melting point, at -26 °C), and depending on the cooling technology the time ranges from 8 to 24 hours. The freezing temperature must be at least 5 °C below the melting point, with an air gap left between the plates.
An example: a set leaves in the morning, spends 12 hours on the route, needs 2 hours for return and cleaning, and 24 hours of freezing. The cycle is 38 hours; with dispatches every 24 hours one set is not enough and two are needed. If freezing drops to 8 hours the cycle is 22 hours and one set will do.
If three routes leave on the same morning, three separate sets are needed, because one set cannot be counted as ready in two places. A set is the group of plates that must be ready together for one load; if one plate has been taken out of use, the set is not ready until a match is found. Before buying a set, check whether the freezer can freeze that many sets at once: GEBHARDT offers freezing racks for this.
