When the door opens, cold air flows out of the lower part of the body and warm air enters at the top. According to a 2019 study by Rai, Sun and Tassou, this infiltration can account for about 34% of the refrigeration load in delivery trucks, and its share grows as openings get longer or more frequent.
Write the minutes first
At each stop, record the opening and closing times, the door, the type of delivery and any unusual waiting. Open time is the interval from opening to closing and the round total is the sum of those intervals; one minute per stop is half an hour over thirty stops. Place loggers separately beside the product and near the door and write down their positions, because a logger on the back wall will not show that the pallet by the door has warmed and been re-chilled again and again.
Get the litres by comparison
Run the same route and load with two door routines, for example the current one and loading in delivery order. Set total open time, temperature beside the product, the fuel or energy meter and delivery delay side by side, changing one thing at a time.
If the cold sits next to the load, the picture changes: in a GEBHARDT Isotec TBX only the lid of the container being delivered opens and the other containers stay closed. On a thirty-stop round that means controlled openings instead of thirty small events.
