A reefer works on an air loop, and loading follows that loop:
- The unit cools the air and blows it towards the doors between the T-shaped floor profiles.
- The air rises through and around the cargo. For that the load covers the floor but does not project beyond the T profiles, and stays below the red load line.
- Warmed air returns to the unit along the ceiling; the unit records supply and return air temperatures.
The record shows air, not cargo, so product temperature is measured separately at loading and at delivery. Cargo is loaded at its target temperature, because a reefer is designed to hold a condition.
Where it does not work
The unit plugs into a socket at the depot, in port and on the ship, and into a generator set on the road. Every hour without power leaves the cargo to the polyurethane insulation alone, and as the insulation ages the container warms faster. Whose responsibility the socket at the waiting yard is should be a separate line in the rental offer.
For store delivery and city rounds a reefer is both too large and tied to a socket. On that layer the cold comes from pre-frozen eutectic plates inside an insulated container; GEBHARDT Isotec containers keep the cold chain for up to 24 hours with eutectic plates or dry ice.
