Why Produce Needs Forced-Air Precooling Inside Its Boxes
Cooling the room air does not instantly cool the produce inside a box. Packaging and the spaces between fruit limit how readily cold air reaches the warm load.
Follow the air through the process
Create a pressure difference across the boxes
In a tunnel precooler, two pallet rows form a central channel. A cover seals the top and far end. The extraction fan lowers pressure in that channel, drawing room air through the load.
Air must pass through the package openings
Aligned vents let air enter the carton, pass between individual pieces of produce and reach the central channel. A solid liner or blocked opening can interrupt this route.
Leaks provide an easier route
A gap in the cover can let air enter the channel without crossing the fruit. The fan may still move a large volume, while useful through-package flow falls.
Measure the produce, not only the room
Heat must move from the produce into the air, then to the room’s refrigeration system. Check temperatures inside representative packages, including positions that cool more slowly.
Airflow function
- Create the pressure difference that draws cold air through the packaged load.
- Carry heat from the produce toward the cold-room conditioning system.
- Provide useful through-package flow while the sealed cover limits easier bypass routes.
What can change the result
- Blocked carton vents prevent cold air reaching produce inside.
- Gaps around the cover bypass the useful through-package path.
- Room-air readings alone miss warm positions inside the load.
Start with the complete air path
Share your layout and the information you already have. Unknown values can be identified before a configuration is selected.
Match the fan to this air path
Evaluate LONGWELL EC backward-curved families for the extraction assembly. Supply package and pallet resistance, target through-load flow, air temperature, humidity and the available control range before model selection.
Where it sits
At the extraction end of the covered channel between pallet rows. Lower pressure in that channel draws cold-room air through package vents and the produce load.
Why consider this configuration
The extraction assembly must deliver useful through-load flow at the loaded packaging and tunnel resistance. Cover leaks, cold humid exposure, controls and refrigeration capacity must be reviewed together.
Check the result in your equipment
Discuss your forced-air produce precooling requirements
Send the commodity, target product temperature, carton vents, pallet layout and tunnel seals. Include useful through-load flow, pressure loss, cold-room conditions and control requirements for an extraction-fan review.
A layout, installation photos or your existing model is enough to start the discussion.