Cold store - Racked
The flow should be directly down every other aisle if possible, with the alternating aisles left for return airflow. Flow across the tops of the racks is very disruptive and leaves no clear return path for the air. Air units placed opposite from the doors in freezers will have to penetrate the warm air pocket that rises up from the open doors. This will require a high velocity. Conversely, air units placed on the dock wall of a freezer will be subjected to high infiltration loads unless internal vestibules are used.
Cold store - Unracked
Unracked rooms generally have ceiling heights of 3-5 meter. Therefore, the airstream does not have to fall far to be disrupted by the pallets or totes. Evaporators with propeller fans will only throw 15-18 meter in these conditions. Axial fan units will throw up to 30 meter. The airflow out of an evaporator without long throw adaptors will diverge out by approximately 10 to 15 degree per side.
You want to know more about evaporators placement? Contact yourlocal BAC representative for more information.