It is a perfect system to separate all de different products, varieties, sizes, and qualities. The standard European size for boxes is 1200 mm x 1600 mm x 1230 mm.
Direct pressure system
A direct pressure system with closed boxes is a direct system, which means that 100 % of the conditioned air is forced to pass the product. The pressure system for boxes is a relatively expensive system because of the use of (expensive) specially designed closed boxes and the system needs lots of space.
This pressure system for closed boxes will mainly be used as a drying system for onions, garlic, and flower bulbs. It is also used in areas with a lot of rain during harvest.
Advantages:
- Quick-drying
- Highly controllable product conditions
- Expensive because special boxes are needed
- A lot of space is needed
Direct aspiration system
The aspire system for open boxes is also a direct ventilation system. The air in the room is conditioned and then sucked through the boxes. All kinds of standard open boxes can be used for this system. It is quite a flexible system because the product can be dried and conditioned in the same place with the same system.
Advantages:
- Drying and conditioning of the product with the same system
- Highly controllable product conditions
Disadvantages:
- A sophisticated air plenum is needed
Indirect room ventilation system
With indirect room ventilation, the room air will be conditioned and through natural convection, the air will pass the product. The indirect room ventilation system for open boxes is the most flexible box system.
It doesn’t matter in what way the boxes are placed in the room, different sizes of boxes can be used, even for short time, different products can be stored in the same room. Especially for daily fluctuating demand room ventilation system is very flexible.
The wet product cannot be dried effectively with a room ventilation system, so products that have to be dried after harvest should be dried in a direct system before they will be put in the room ventilation storage.
Advantages:
- Quite an inexpensive system
- Very flexible system
Disadvantages:
- The product cannot be dried
- Harder to control the product conditions